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Senior Science
HSC Course
Stage 6
Medical technology – bionics
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Acknowledgments
This publication is copyright Learning Materials Production, Open Training and Education Network – Distance
Education, NSW Department of Education and Training, however it may contain material from other sources which
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following people and organisations whose material has been used.
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Senior Science Stage 6 Syllabus, Board of Studies, NSW, Amended November 2002
•
Photographs and X-rays courtesy of Fran Philipson, Orana Radiology, Shelley Hudson, Ingrid Kaschik, and
Rizwan Gaffer Masood.
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Writer:
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Editor:
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Di Skelton (Karabar DEC)
Maria Gavranic (Sydney Secondary DEC)
Yvonne Kinch (OLP)
Jenny Glen
Jim Stamell
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© Learning Materials Production, Open Training and Education Network – Distance Education, NSW Department
of Education and Training, 2000. Revised November 2002 51 Wentworth Rd. Strathfield NSW 2135.
Contents
Module overview ....................................................................... iii
Resources............................................................................................ iv
Icons .................................................................................................... vi
Glossary.............................................................................................. vii
Part 1: Spare parts ..............................................................1–33
Part 2: Fixing a broken heart ...............................................1–28
Part 3: Heart to heart...........................................................1–30
Part 4: Bone to bone ...........................................................1–38
Part 5: Breathing easy.........................................................1–30
Part 6: Peek-a-boo ..............................................................1–25
Student evaluation of module
Introduction
i
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Medical technology – bionics
Module overview
Welcome to the Medical technology–bionics module for the HSC
component of the Senior Science course.
This module deals with parts of the body that can be replaced or treated
to improve the health and/or quality of life of an individual.
You will understand how the heart works and the use of biomaterials
used in conjunction with the heart such as artificial heart valves and
pacemakers.
You will learn some of the causes of hardened arteries and the various
medical procedures which aim to restore blood flow in diseased arteries.
Artificial joints used in small and large joints are addressed and the
substances they are made of are explained.
Various medical procedures used in diagnostic medicine such as
magnetic resonance imaging (MRI), X–rays and keyhole surgery are
explained on an audiotape/internet audio files.
You will also be involved in linking technological developments to new
medical procedures which aim to improve medical procedures and
patient recovery time.
Be prepared to have a healthier lifestyle after completing this module!
Introduction
iii
Resources
Internet access is essential for many parts of this module. If you do not
have Internet access at home seek out Internet access at a public library,
internet café, TAFE, school or friend’s place.
You will need the following equipment to carry out activities and
experiments during the module. In most cases, you should have many of
the items listed around your home.
Part 1
• Bionics audiotape/internet audio files
• stop watch or clock with a second hand
Part 3
• coloured pencils or felt tip pens
• glass, glass jar
• uncooked chicken leg bone
• white vinegar
Part 4
• fresh chicken wing
• small pair of scissors
• small sharp knife
• tweezers
• board or dish to hold the specimen being dissected.
• mortar and pestle–optional
• silicone strip
Part 5
• information sources for medical technological developments
• scissors
• glue
• calcium hydroxide (builder’s or mortar lime)
• medium jar
• two small clean glasses
• straw
• small whisk or fork
Part 6
•
•
iv
Blu Tac® or plasticine
ruler
Medical technology – bionics
Icons
The following icons are used within this module. The meaning of each is
written beside it:
The hand icon means there is an activity for you to do.
It may be an experiment or you may make something.
The talk icon guides you to discuss a topic with others.
There are exercises at the end of each part for you to
complete and send to your teacher.
The headphone icon asks you to complete an activity while
listening to an audio tape.
The safety glass icon points out that care needs to be taken
when carrying out a task.
There are suggested answers for the following questions at
the end of each part.
The computer mouse icon refers to an Internet website you
may wish to visit for additional information.
Introduction
v
Glossary
The following glossary provides a scientific meaning for many of the
term used in this module, Medical technology–bionics.
The HSC examiner will expect you to understand the meaning of every
scientific term used. If you find a term that you do not understand, then
look it up in a scientific dictionary or ask your teacher for assistance.
vi
acetabular component
component that fits into cup–shaped socket in the
pelvis
alveolus
site of gas exchange in the lung; sac in the lung
surrounded by a network of capillaries (plural:
alveoli)
aneurysm
abnormal enlargement (dilation or outpouching) of
the artery wall
angioplasty
repair of a blood vessel
aorta
blood vessel; carries oxygenated blood from the heart
to the body except the lungs
arhythmia
irregularity or loss of rhythm of heartbeat
arteriosclerosis
a number of diseases in which the walls of the
arteries become thickened and lose their ability to
stretch; commonly called ‘hardening of the arteries’
artery
large muscular blood vessel carrying blood to body
tissue from the heart
artery plaque
layers of cholesterol, blood and cell fragments that
coats artery walls
articular cartilage
cartilage on the ends of bones in a joint
atherectomy
removal of plaque from artery wall using a catheter
with a cutting blade
atherosclerosis
building up of fatty deposits to form plaque in the
innermost layer of the artery wall; the most common
form of arteriosclerosis
arthroscope
long, thin tube with a camera at one end which is
inserted into joints to assess joint damage
artificial heart valve
synthetic device allowing the flow of blood in one
direction when implanted in the heart; replaces
diseased heart valves
artificial lung
an implant in a vein delivering oxygen to blood and
removing carbon dioxide from blood
Medical technology – bionics
Introduction
artificial respirator
forces air into lungs and removes air from lungs to
maintain gas exchange in a patient who is not
breathing
atherectomy
removal of the plaque from the artery wall using a
catheter with a cutting blade
atlas
first vertebra of the backbone
atrium
upper heart chamber delivering blood to the
ventricles
atrioventricular (AV)
junction
junction through which electrical impulses from the
sinoatrial node travel to the ventricles from the atria
in the heart
autoimmune disease
body’s immune system attacks a body part
axis
second vertebra with a peg–like projection
ball and socket joint
the end of one bone is shaped like a ball which fits
the end of another bone that is shaped like a cup or
socket
balloon angioplasty
a catheter is inserted into an artery in the groin and
manouvered to the obstructed artery where a balloon
at the end of the catheter is repeatedly blown up and
deflated to push artery plaque against artery walls,
widening the artery
bicuspid valve
heart valve with two flaps for blood to flow through
biocompatible
non–reactive with body tissue or body fluids
biomaterial
material compatible with body tissue which can be
used for implants
biomedical
medicine applied to the biological structure of
organisms
bionic ear
see cochlear implant
bionics
the scientific study of living things as functional
models for technical development of therapeutic
devices, which imitate the functions of particular
body parts
blood clot
blood forms a hard seal to minimise bleeding
bone marrow
tissue in the cavity of long bones: red and white
blood cells are produced here
bradycardia
a very slow heart beat at rest of around 40 beats per
minute
bronchi
divide into bronchioles in the lungs; plural of
bronchus; two main branches of trachea in the lung
vii
bronchiole
air passage to and from the alveoli
bundle branch block
the AV junction in the heart fails to transmit some
electrical signals to the ventricles
bypass surgery
veins from other parts of the body are removed and
placed in an area to bypass a blocked artery;
alternatively small arteries in the chest are redirected
to the heart
calcified
become hardened by calcium salts
calcium phosphate
salt which hardens the collagen matrix in bones
cancellous bone
spongy bone at the ends of long bones
capillary
very small blood vessel carrying blood to and from
body tissue
cardiac
of the heart
cardiac arrest
the heart is fibrillating as a result of unsequenced
cardiac contractions
cardiac catheterisation a diagnostic study to evaluate the coronary arteries
viii
cardiomyopathy
any disease of the heart muscles; usually produces an
enlarged heart
cardiopulmonary
resuscitation (CPR)
A combination of external cardiac compression
(ECC) and expired air resuscitation (EAR) to
maintain heart and lung function of the body
cartilage
strong flexible substance made of collagen; cartilage
is used to support and protect the body from shocks
and impacts; the ends of the bone are covered with
cartilage to make a smooth, flexible joint which
minimises friction between the surfaces of the joint
catheter
tube passing into body
cellular respiration
chemical reactions which release energy for
organisms
cemented
a plastic compound is used as a type of grouting
material, forming an interlocking mechanical bond
with the bone holding artificial joints in place
circulatory system
arteries, veins, capillaries and the heart delivers
oxygen and nutrients to cells around the body and
removes wastes
cobalt/chromium
alloy
hard white/silver mix of the metals cobalt and
chromium which is resistant to corrosion, is durable
and biocompatible; used in biomedical implants
cochlea
spiral–shaped part of the inner ear which delivers
sounds to the brain as electrical impulses
Medical technology – bionics
Introduction
cochlear implant
electrodes implanted into the cochlea assist in
delivering electrical impulses from sounds to the
cochlea, improving hearing
collagen
strong, flexible organic substance; present in joints as
bands which hold the joint together and allows it to
move freely
complete heart block
an interference with the normal conduction of
electrical impulses that control activity of the heart
muscles
crown
tooth cap made of a hard substance such as porcelain
CT (computerised
tomography) scans
A thin beam of X–rays generated by a conventional
X–ray tube passes through a single 'slice' of a patient
through to a bank of X–ray detectors. By taking
thousands of readings from multiple angles around
the patient, a two or three dimensional image can be
reconstructed.
defibrillator
paddles which deliver an electric charge to the chest
of a person suffering a cardiac arrest
destructive testing
when during testing, a chemical reaction takes place
that alters the chemical nature of the specimen
diaphragm
thin muscular sheath separating the intestines from
the lung tissue; responsible for creating differences in
air pressure within the lungs
diaphysis
long straight section of a bone; shaft of a long bone
diffusion
random movement of particles from areas of high
concentration to areas of low concentration
DNA tests
the genetic make up of a person is mapped
double hinge joint
a hinge joint that allows sideways movement
electrocardiograph
(ECG)
the heart’s electrical activity is electronically
measured and graphically represented, showing any
irregular heart activity or damage to heart muscle
endoscope
long, thin tube with a camera at one end which is
inserted through any internal part of the body to
assess internal digestive and urinary conditions
epiphysis
the ends of bones
exhale
to breathe out
expired air
resuscitation (EAR)
delivering air to the lungs of a person who is not
breathing
external cardiac
compression (ECC)
regular compression of the breastbone when the heart
has stopped beating to pump blood around the body
ix
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externally
outside
femoral head
ball shaped top end of femur bone in leg
fibrillation
electrical impulses in the heart cause the heart to
quiver rather than contract; no effective blood
movement results
hardened arteries
a number of diseases in which the walls of the
arteries become thickened and lose their ability to
stretch
heart attack
blood flow to heart muscles is impaired limiting the
heart’s ability to contract
heart–lung machine
pumps blood around the body and exchanges gases
with the air
heart transplant
replacing a diseased heart with a healthy heart from a
donor
heart valve
folds of tissue around an opening that allow blood to
flow in one direction only through the heart
high density
lipoprotein (HDL)
‘good’ cholesterol which assists in removing LDL
from artery walls
hinge joint
the extremities of two joining bones fit like a hinge
humerus
the bone in the upper arm
inhale
drawing air into the lungs
(heart valve)
insufficiency
where the valve does not close completely
internal
inside the body
joint
the place where two or more bones meet
keyhole surgery
a tiny camera and light on the end of a probe allows a
surgeon to detect abnormalities within the body and
carry out surgery without opening the body
laser angioplasty
a thin tube (catheter) is inserted into an artery and
moved through the blood vessels to the blocked
artery. The laser emits short pulses of photons that
cause the plaque to vaporise
ligament
strong band of collagen connecting two bones at a
joint. Restricts unwanted movement of the joint and
helps to prevent dislocation.
lipoproteins
fatty protein which carries cholesterol in the blood
stream
low density
lipoprotein (LDL)
‘bad’ cholesterol often deposited on artery walls
Medical technology – bionics
Introduction
lungs
a network of millions of tiny air sacs and
bronchioles; site of gas exchange
magnetic resonance
imaging (MRI)
X–rays of slices though part of the body taken to
show organ abnormalities; slices may be compiled to
create a three dimensional image showing the extent
of the abnormality
mammogram
X–ray of breast tissue
molybdenum
a metal that forms strong biocompatible, durable
alloys used in biomedical implants
mortar and pestle
mortar is a bowl with a smooth round interior used to
grind solids with a hand held pestle
nasal cavity
warms, filters and moistens the air drawn into the
lungs
non–destructive
testing
allows data collection without changing the chemical
components of the specimen
pacemaker
artificially paces heartbeat via electrodes placed
inside, or on the surface of, the heart. The pacemaker
delivers electrical impulses to the heart via these
electrodes.
pharynx
passageway through which air travels on the way to
the trachea
plaque
deposit formed from fatty material and cholesterol
that forms on the inside walls of arteries
pivot joint
joint capable of rotation; rotates around a peg–like
projection of a bone
prosthetic
an external artificial body part
pulmonary artery
carries deoxygenated blood from the heart to the
lungs
pulmonary vein
carries oxygenated blood from the lungs to the heart
to be pumped to the body
(heart valve)
regurgitation
where the valve does not close completely
respiratory system
the system which is responsible for respiration
(gaseous exchange in the lungs of oxygen from
inhaled air into the bloodstream, and carbon dioxide
from the bloodstream into exhaled air).
rotoblator
catheter with a diamond tip which rotates at a high
speed and breaks the plaque into microscopic
particles
saddle joint
synovial joint where one bone rests in a saddle–like
impression of another bone
xi
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sick sinoatrial node
syndrome
the sinoatrial node or the atria are damaged, causing
the atria not to contract properly
silicone
organic compound which is non–reactive with body
tissue
sinoatrial (SA) node
a group of cells located in the right atrium which
sends electrical impulses causing the heart chambers
to contract
sliding joint
allows movement from side to side or back to front
stainless steel
an alloy of iron, carbon, chromium which is highly
resistant to corrosion; is biocompatible and used in
biomedical implants
stenosis
where the valve opening becomes narrow
stent
device inserted in a narrowed area of a coronary
artery to expand the artery
stethoscope
instrument which amplifies sounds such as the heart
beat
stroke
interruption of blood flow in the brain; may be
caused by a blood clot to the brain or a ruptured
artery in the brain
superalloy
cobalt/chrome or titanium alloy
synovial fluid
fluid which lubricates joints
synovial joints
joints containing synovial fluid for joint lubrication
and movement
synovial membrane
inside layer of the synovial capsule that secretes
synovial fluid
tachycardia
abnormal rapid heart action
tendon
tough, rope–like strands which connects muscle to
bone
thermography
images of the body’s infra–red radiation shows
relatively hot and cold areas of the body
thrombectomy
the removal of a thrombus, or clot, which is
obstructing blood flow
titanium
used in artificial joints; durable, lightweight, strong
biocompatible material
trachea
connects pharynx to bronchi
tricuspid valve
heart valve with three flaps for blood to flow through
ulna
bone in the lower arm
Medical technology – bionics
Introduction
ultra high molecular
weight polyethylene
(UHMWPE)
rubbery durable substance covering articulating ends
of load bearing artificial joints reducing joint friction
ultrasound
sound waves are reflected off internal organs,
detected and displayed as a visual image on a screen
uncemented
artificial joints are inserted into bone; the bone grows
to attach itself to the porous artificial joint surface,
holding it in place
vein
blood vessel carrying blood from body tissue towards
the heart
ventricle
bottom heart chamber responsible for pumping blood
to the lungs and body
ventricular
tachycardia (VT)
rapid contractions cause the heart to beat too quickly
while at rest; can prevent the heart from filling with
blood between beats
vertebrae
the small bones which surround the spinal cord and
together make up the spinal column or backbone
X–ray
detected by a photographic sheet after passing
through a part of the body; the images are used to
detect abnormalities
xiii
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Senior Science
HSC course
Stage 6
Medical technology – bionics
Part 1: Spare parts
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Lifestyle chemistry
Medical technology – bionics
Spare parts
Fixing a broken heart
Heart to heart
Bone to bone
Breathing easy
Peek–a–boo
Information systems
Option
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Contents
Introduction ............................................................................... 2
Implants and biomedical devices .............................................. 4
Biomedical devices used externally ....................................................4
Biomedical implants .............................................................................7
The circulatory system ............................................................ 10
The heart ............................................................................................10
Cardiac contractions ..........................................................................14
Summary................................................................................. 19
Appendix 1 .............................................................................. 21
Appendix 2 .............................................................................. 23
Suggested answers................................................................. 25
Exercises – Part 1 ................................................................... 29
Part 1: Spare parts
1
Introduction
In Part 1, you will be given opportunities to learn to outline: the role of
the heart in maintaining human life, the functions of different parts of the
heart; heart conditions and medical responses to such problems.
You will learn how pacemakers maintain heartbeat and the history of
their development.
In this part you will be given opportunities to learn to:
•
•
2
identify parts of the body and the biomaterials and biomedical
devices that can be used to replace damaged or diseased body parts
including
–
pins, screws and plates
–
artificial joints
–
pacemakers
–
artificial valves
–
crowns, dentures
–
lenses
–
prosthetic limbs
–
cochlear implants
explain the relationship between the structure and function of the
following parts of the heart
–
valves
–
atria
–
ventricles
–
major arteries and veins
•
explain that specialised tissues in the heart produce an electrical
signal that stimulates rhythmic contractions of the cardiac muscle
•
discuss problems that can result from interruptions to the normal
rhythm of the heart.
Medical technology – bionics
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In this part you will be given opportunities to:
•
gather and process information from secondary sources to trace the
historical development of one of the following implants:
– cochlear implants
– artificial valves
•
gather, identify data sources, plan, choose equipment or resources
for, perform a first hand investigation and analyse information about
changes in the heartbeat rate before and after physical activity
•
plan and perform an investigation to identify individual aspects that
comprise the heartbeat
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
November 2002. The most up-to-date version is to be found at
http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
Part 1: Spare parts
3
Implants and biomedical devices
Human body function may be assisted by many biomedical devices and
biomaterials. You, or a member of your family may even use some of
these devices.
These devices can be separated into those used externally and internally
(implanted).
Biomedical devices used externally
1
The following diagrams show a range of biomaterials used to assist or
replace damaged or diseased body parts externally. Use the words
below to write the correct name next to each diagram:
prosthetic limbs; eyeglasses; crowns; contact lenses; dentures.
Diagram
4
Name
Medical technology – bionics
Gill Sans Bold
Check your answers.
Do you or any of your family members use any of these external devices?
Outline each device, who uses it and how it helps.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Listen to the Biomedical devices section of the Bionics audiotape/internet
audio files at www.lmpc.edu.au/science (go to Senior Science, go to Medical
Technology, go to Bionics audio). Use the information in the audiotape to
record relevant information for each external biomedical device in each
column on the following page.
Part 1: Spare parts
5
Answers are not provided for this activity to encourage you to complete
the task.
6
Medical technology – bionics
prosthetic limbs
contact lenses
glasses
dentures
crowns
Biomedical
device
Where used on
the body
Component
material
Benefits of use
History of development
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Biomedical implants
Have you heard of ear implants; metal pins screws and plates inserted
into bones; artificial hip and knee joints; pacemakers; and artificial heart
valves? These are all examples of biomedical devices that are implanted
into the body to assist body function.
Cochlear implants
© The Bionic Ear and The University of Melbourne
A cochlear implant, also known as a bionic ear, can markedly improve
communication for a severely hearing impaired person.
During careful surgery an electrode is placed into the spiral cochlea,
making contact with nerve endings (shown in the diagram on the right
below). The electrode is attached to an implant lying just under the skin
behind the ear. Outside the skin, above the implant, sits a transmitting
coil. The coil receives electrical signals from a speech processor which
is connected to a microphone behind the ear.
A microphone collects sounds which are processed into electrical
signals then sent to the transmitter coil. FM radio waves transfer sound
information to the implant under the skin. The implant receiver
transmits the signals to the electrode inside the cochlea. These electrical
signals stimulate nerve endings in the cochlea which are then converted
into sounds by the brain. The diagram below demonstrates the
internal implant and the external attachments associated with the
cochlear implant.
microphone
hook over ear
implant receives radio
waves (and sends signals
through electrode)
electrode stimulates nerve
endings inside cochlear
speech
processor
ear drum
transmitting coil (sends FM radio
waves through skin to implant)
Cochlear implant with external attachments.
Part 1: Spare parts
7
An Australian scientist, Dr Graeme Clark invented the cochlear implant.
His research into electrically stimulated hearing since 1970 led to the
development of the Bionic Ear Institute in 1984. The Melbourne institute
is still successfully carrying out cochlear implants today.
Go to www.lmpc.edu.au/science, click senior science, then click medical
technology – bionics to find links such as the Cooperative Research Centre
for Cochlear Implant and Hearing Aid Innovation.
Pins, screws and plates
Metal pins, screws and plates are often used to keep bones in place while
healing, replace parts of bones such as part of the skull and hold artificial
joints in place. The diagram below show pins and screws in place inside
an ankle while the broken bones heal.
X–ray of pins and screws in place inside an ankle.
Reproduced by permission Ingrid Kaschik
Medical metal implanted in the body is generally made from alloys such
as titanium/cobalt/chromium/molybdenum or stainless steel.
These metals will not corrode once in the body and are strong enough to
hold bones together for many years.
Other biomedical implants such as pacemakers, heart valves and artificial
joints are addressed in Parts 1 to 4.
8
Medical technology – bionics
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You are required to record data on:
•
the type of implant
•
the material from which it is made
•
the part of the body where it is commonly used.
If you have access to a computer database package, you could carry out
the following activity using a database. If you do not have access to a
database package you can store data in a table provided in Appendix 1.
Turn to Appendix 1 at the back of this part. Appendix 1 explains an
activity you must start now and send in with the exercises in Part 4.
You will be instructed to add to the information in Appendix 1 during
Parts 1, 2, 3 and 4 with the following reminder:
Add relevant information on implants to the database or table in Appendix 1
from Part 1. This information will be returned with the exercises in Part 4.
Part 1: Spare parts
9
The circulatory system
When was the last time you cut yourself? Did you bleed much?
That blood was meant for the cells in that part of the body. It was
supposed to take nutrients and oxygen to cells and remove carbon
dioxide and wastes from cells instead of flowing onto the skin’s surface
and staining your clothes.
Blood circulates around the entire body, taking nutrients (from food) and
oxygen (from the lungs) to cells in the body. What keeps the blood
pumping through your arteries, veins and capillaries? That’s right–its
the heart.
Your circulatory system is made up of the heart and all the arteries,
veins and capillaries in your body. Without your circulatory system to
provide essential things such as nutrients and oxygen to your cells, your
body would cease to function.
The heart
Your heart is essential to your life. Have you ever thought about how
much work it must do in a day just to keep you alive? On average, your
heart beats 70 times in a minute. That calculates to over 4200 times an
hour and over 100 000 a day–and that’s without exercise!
This section takes a closer look at this major organ and its structure.
1
Listen to The heart section of the Bionics audiotape/internet audio files.
Use this information to complete the labels indicated with letters on the
diagram of the heart on the following page.
These letters match those in the table on the following page.
Write the correct labels in the table.
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Letter
Label
A
B
C
D
E
F
G
H
I
J
K
body
L
to the
he lungs
to t
L
G
F
A
H
f
m
ro
y
bod
e
h
t
B
I
E
K
C
D
J
View of the heart as though seen in a person facing you. The left side of the
heart is on your right.
Part 1: Spare parts
11
2
Answer the following true/false questions based on the information
from the previous activity.
a) Blood from the aorta travels to the body
T
F
b) Blood moves into the left atrium through the
tricuspid valve
T
F
c) Blood travels through the pulmonic valve from the
right ventricle
T
F
d) The vena cava delivers blood to the heart from the
lungs
T
F
e) The left side of the heart contains oxygen rich blood
T
F
f)
T
F
T
F
T
F
T
F
The right side of the heart contains blood rich in
carbon dioxide
g) The pulmonary vein sends blood to the left ventricle
h) The aortic valve opens, allowing blood from the left
ventricle into the aorta
i)
3
The left ventricle is more muscular than the right
ventricle.
Complete the sentences in the following passage using the
information from the previous activities.
•
The blood enters the heart from the ___________ through the
vena cava. It enters the _____________ _____________,
travels through the _____________ _____________ and flows
into the right _____________.
•
The muscle surrounding the right ventricle _____________,
pushing blood through the ______________ _____________.
•
Blood then travels to the lungs through the _____________
_____________.
•
Here it exchanges carbon dioxide for _____________.
The blood then flows back to the heart through the
______________ ______ into the _______ __________.
•
Once the left atrium fills with blood, the _____________
_____________ opens to allow blood into the _____________
_____________.
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•
The left ventricle then contracts, pushing blood through the
_____________ _____________ into the _____________.
•
From here, oxygen rich blood is circulated around the body,
giving _____________ and nutrients to cells.
Check your answers.
As your heart beats, blood flows through arteries in pulses. You can feel
these pulses on certain parts of the body. The most common places to
feel these are on the wrist and neck. If you have ever taken your pulse,
you might have had some difficulty finding it on your wrist. For this
reason it may be easier to take your pulse on your neck.
Person taking pulse.
Place two fingers on your neck as shown above, but don’t press too hard.
You should feel your pulse beating. If not, press a little harder or softer
until you feel your pulse.
You will be taking your pulse in the following activity.
Heart rate and physical activity
You will be investigating changes in the heartbeat rate before and after
physical activity. You will plan your own investigation in Exercise 1.1.
Before attempting Exercise 1.1, read through an investigation planned by
a student in Appendix 2, then answer the following questions.
Part 1: Spare parts
13
1
Describe one thing that would be improved in this scientific report.
_____________________________________________________
2
Re–write the conclusion using scientific language, replacing the words
‘I’ and ‘my’ with words such as ‘it is thought’ or ‘the results indicate’.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
Turn to Exercise 1.1 at the back of this part to plan and carry out an
investigation on heart rate at rest and with sustained physical activity.
Cardiac contractions
The term cardiac refers to the heart. Cardiac muscle refers to muscles in the
heart. You might wonder how the cardiac muscles know when to contract.
The answer lies in specialised cells and electrical impulses within the heart.
Specialised cells on the wall of the right atrium are located in the sinoatrial
(SA) node. These cells are a natural pacemaker, starting an electrical chain
reaction. An electrical impulse from the SA node causes the atria to contract.
This sends blood through the valves to the ventricles on both sides of the heart
as shown in the diagram below.
sinoatrial node
sending impulse to
atrium muscles
to contract
blood is forced
into the ventricles
Atria contracting.
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sinus
node
impulse from
the sinoatrial node
moves through
the AV junction
to the ventricles
causing the ventricle
muscles to contract.
This forces blood into
the aorta and pulmonary
artery.
Ventricles contracting, sending blood from the heart to the lungs and body.
The electrical impulse from the atria passes to an atrioventricular (AV)
junction to the ventricles. The AV junction can be likened to wires
between the atria and ventricles. The impulse is slowed here, before
being passed to the ventricles. This allows the atria to relax (and fill with
blood) before the ventricles contract.
1
What initiates electrical impulses in the heart?
_____________________________________________________
_____________________________________________________
2
What does the initial electrical impulse cause?
_____________________________________________________
3
How does the electrical impulse get to the ventricles?
_____________________________________________________
4
Why does the AV junction slow the impulse?
_____________________________________________________
_____________________________________________________
5
What do you think would happen if the electrical signals became
unsequenced?
_____________________________________________________
_____________________________________________________
Check your answers.
Part 1: Spare parts
15
The heartbeat
Have you ever listened to a heartbeat through a stethoscope? If so, you
should have heard the ‘thump thump’ sound of the heart.
After completing the previous section, you should already have your own
ideas as to why the heart makes a double beat sound.
The first beat is caused by the tricuspid and bicuspid valves closing after
atria muscles have contracted squeezing blood into the ventricles. The
second beat is caused by the closing of pulmonic and aortic valves after
the ventricles contract, pumping blood around the body and to the lungs.
You will now plan an investigation to identify individual aspects that
comprise the heartbeat for ten seconds.
What is the best way for you to hear a heartbeat? A stethoscope would do
this job well, however its unlikely you have one at home. Holding your ear
to a person’s chest or back may be the only option. Ask a willing person at
home if you can listen to their heartbeat for about ten seconds.
1
What did you hear? Describe the sounds below.
_____________________________________________________
_____________________________________________________
2
With your knowledge of the heartbeat, explain why the heart sounds as
you described above.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
The sound of a heartbeat is often described as ‘lub–dub’ or ‘lubb–dupp’.
Lub or lubb, a long low–pitched sound, is produced by the closing of the
valves between the atria and ventricles. Dub or dupp, a short, louder and
high–pitched sound, comes from the closing of the valves between
ventricles and the aorta and pulmonary artery.
If a valve is damaged it cannot close completely and blood flow is more
turbulent as blood leaks backwards. Certain blowing or whooshing
sounds can be used to diagnose heart problems.
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Interrupting the heartbeat
Some people’s heart can beat too quickly while at rest. The rapid
contractions can prevent the heart from filling with blood between beats.
This condition is called ventricular tachycardia (VT). Symptoms of
VT are weakness, dizziness and fainting. These symptoms are caused by
poor delivery of oxygen enriched blood to the body.
Other people may have poor AV node junctions. Imagine the AV
junction as a bundle of wires joining the atria to the ventricles.
Bundle branch block is caused by one or two ‘wires’ failing to
transmit electrical signals. The heart can still function normally under
these conditions, however if all the ‘wires’ cease to function, the
electrical signal will not be transmitted to the ventricle. This is called
complete heart block. The symptoms of complete heart block are
similar to VT symptoms.
A condition causing a very slow heart beat at rest of around 40 beats per
minute is called bradycardia.
VT, bundle branch block, complete heart block and bradycardia are
forms of arhythmias. This means abnormal beating. Another cause of
abnormal beating can be sick sinoatrial node syndrome. In this
instance the sinoatrial node or the atria are damaged, causing the atria not
to contract properly. Symptoms of sick sinoatrial node syndrome are
tiredness, shortness of breath and fainting.
Disrupted electrical signals in the heart can cause the heart to stop
beating or to quiver instead of pumping. The heart quivering is called
fibrillation. Cardiac arrest is the name given to conditions in which
the heart stops pumping. (Cardiac arrest is not to be confused with a
heart attack, which is caused by a lack of blood to the heart
tissue itself.)
In each instance of cardiac arrest, cardiopulmonary resuscitation
(CPR) should be commenced in an attempt to push oxygenated blood
around the body until the heart can resume its normal pattern of beating.
In the case of cardiac arrest, external defibrillators can be used to send
an electric pulse through the body, to stop the irregular beating of the
heart, allowing it to return to a normal rhythm. You may have seen
external defibrillators used in medical television programs to revive a
patient whose heart is fibrillating.
Part 1: Spare parts
17
1
Imagine you are a doctor. A patient has come to you complaining of
weakness and a fluttering feeling in their chest. You begin to explain
the main cause for such a feeling. In the space below explain in writing
what causes that feeling, what it is called and what other symptoms can
result from the condition.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
2
What causes a cardiac arrest?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
3
How may cardiac arrest be treated?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Check your answers.
Turn to Exercise 1.2 to summarise the symptoms and conditions of an
irregular beating heart.
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Summary
Reconstruct the following words then write a brief description explaining
each term.
1
ucilorrcaty smstey
_____________________________________________________
_____________________________________________________
2
itruma
_____________________________________________________
_____________________________________________________
3
envietrcl
_____________________________________________________
_____________________________________________________
4
nussi deno
_____________________________________________________
_____________________________________________________
5
marsyhihta
_____________________________________________________
_____________________________________________________
6
wconr
_____________________________________________________
_____________________________________________________
7
ipn
_____________________________________________________
_____________________________________________________
Part 1: Spare parts
19
8
hocrclea lpimnta
______________________________________________________
______________________________________________________
9
libiimoaedc vdicee
______________________________________________________
______________________________________________________
10 etahr rtae
______________________________________________________
______________________________________________________
Check your answers.
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Appendix 1
Extract information from Parts 1, 2, 3 and 4 to compile a database on
biomedical implants.
You should collect information on:
•
type of implant
•
component materials of the implant
•
part of the body where the implant is used.
You may need to seek help from your teacher or supervisor.
If you do not have access to a computer and/or a database program then
complete this exercise by filling in the table on the following page.
This page can be torn out, kept, added to as you learn about the relevant
implants and returned with the Exercise in Part 4. You will receive the
following reminder each time you are required to add information to the
table below.
Add relevant information on implants to your database or table in Appendix 1
from Part 1. This information will be returned with the exercises in Part 4.
Complete the information you have learned on cochlear implants and
pins, screws and plates now.
Part 1: Spare parts
21
Implant type
Component material(s)
Body part commonly involved
cochlear
implant
pins, screws
and plates
pacemaker
artificial heart
valves
small artificial
joints
load bearing
artificial joints
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Appendix 2
Part 1: Spare parts
23
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Suggested answers
Biomedical devices used externally
Diagram
Name
crowns
dentures
eye glasses
contact lenses
prosthetic limbs
Part 1: Spare parts
25
2
3
26
Label
Letter
1
Letter
The heart
Label
A
Vena cava
G
Pulmonary vein
B
Right atrium
H
Left atrium
C
Tricuspid valve
I
Bicuspid valve
D
Right ventricle
J
Left ventricle
E
Pulmonic valve
K
Aortic valve
F
Pulmonary artery
L
Aorta
a) Blood from the aorta travels to the body
T
b) Blood moves into the left atrium through the tricuspid
valve
F
c) Blood travels through the pulmonic valve from the right
ventricle
T
d) The vena cava delivers blood to the heart from the lungs
F
e) The left side of the heart contains oxygen rich blood
T
f)
T
The right side of the heart contains blood rich in carbon
dioxide
g) The pulmonary vein sends blood to the left ventricle
F
h) The aortic valve opens, allowing blood from the left
ventricle into the aorta
T
i)
The left ventricle is more muscular than the right
ventricle.
T
•
The blood enters the heart from the body through the vena cava.
It enters the right atrium travels through the tricuspid valve and
flows into the right ventricle.
•
The muscle surrounding the right ventricle contracts, pushing
blood through the pulmonic valve.
•
Blood then travels to the lungs through the pulmonary artery.
Medical technology – bionics
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•
Here it exchanges carbon dioxide for oxygen. The blood then
flows back to the heart through the pulmonary vein into the left
atrium.
•
Once the left atrium fills with blood, the bicuspid valve opens to
allow blood into the left ventricle.
•
The left ventricle then contracts, pushing blood through the
aortic valve into the aorta.
•
From here, oxygen rich blood is circulated around the body,
giving oxygen and nutrients to cells.
Heart rate and physical activity
1
The student wrote a recount rather than an experimental report.
The student wrote the report using ‘I’ and ‘we’ rather than
impersonal language.
2
Heart rate appears to increase with increased activity. As energy is
used, more blood is required to circulate around the body delivering
oxygen and nutrients to cells. It is thought the heart pumps faster to
deliver more blood to cells.
Cardiac contractions
1
Specialised cells in the sinus node in the right atrium initiates an
electrical impulse in the heart.
2
The initial electrical impulse causes the atria to contract.
3
The electrical impulse passes to the ventricles via the AV junction.
4
The AV junction slows the impulse to allow the atria to relax before
the ventricles contract.
5
If the electrical signals become unsequenced, blood could be
pumped back to the atria instead of passing to the lungs or the body.
Other answers are acceptable.
Interrupting the heart beat
1
Fluttering of the heart is caused by the ventricle’s pumping action
becoming out of sequence with the atria’s pumping action. The
condition is called ventricular tachycardia. Other symptoms it can
cause are weakness, dizziness and fainting.
2
Cardiac arrest is caused by disruption of electrical signals to the
heart. This causes the heart to stop or to fibrillate.
3
Cardiac arrest may be corrected through CPR until the heart’s
electrical activity returns to normal or through the use of external
defibrillators. The defibrillators deliver an electrical impulse to stop
Part 1: Spare parts
27
the heart’s erratic activity, in an attempt to cause the heart to resume
beating normally.
Summary
1
Circulatory system–the heart, arteries, veins and capillaries in the
body circulating blood.
2
Atrium–one of the two top chambers of the heart which fill with
blood and pass blood to the ventricles.
3
Ventricle–bottom chambers of the heart with muscular walls to
pump blood to the lungs and body.
4
Sinus node–group of specialised cells in the right atrium that start an
electrical chain reaction, causing the heart to pump.
5
Arhythmias–the unsequenced or unusual beating of the heart.
6
Crown–can replace missing teeth, cover existing teeth or be attached
to broken or chipped teeth. May be made of porcelain, stainless
steel, polymer glass or gold.
7
Pin–used to hold bones together and join artificial joints to bones;
medical pins are made of cobalt/chromium, molybdenum and
stainless steel.
8
Cochlear implant–electrode implanted into the cochlea to improve
hearing; developed by Dr Graeme Clark–an Australian scientist
from Melbourne.
9
Biomedical device–device used to aid the functioning of the human
body such as dentures, cochlear implants and artificial joints.
10 Heart rate–heart rate increases with increased activity.
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Exercises - Part 1
Exercises 1.1 to 1.3
Name: _________________________________
Exercise 1.1
You must now plan, carry out and report on the relationship between
heartbeat rate at rest and with sustained physical activity. You may refer
to Appendix 2 to help you plan your investigation.
Aim
To investigate the changes in heartbeat rate during rest and sustained
physical activity.
Apparatus
What will you need to carry out your investigation?
_________________________________________________________
_________________________________________________________
Method
How will you carry out your investigation? Present your method as a
procedure.
If you have access to a data logger, it can used to detect and record your
heart rate during various activities.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 1: Spare parts
29
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Before carrying out the activity, predict the outcome you expect from
carrying out the method you outlined (in one or two sentences).
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Results
How will you present your results? They should be easy to read and
clearly show the trend you expect to observe.
Include an appropriate graph of your results. A histogram or bar graph
are ideal choices for the results you are likely to expect. If you are not
sure how to graph your results, refer to the Science resource book or
contact your teacher. Put your results below and your graph on the next
page.
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Don’t forget your graph
Conclusion
What happened to your heart rate with physical activity? Explain your
observations. Comment on any problems or ways of improving the
experiment.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 1: Spare parts
31
Exercise 1.2
In the spaces provided, explain each heart condition and their
accompanying symptoms
Heart condition
Description of condition
Symptoms
ventricular tachycardia
bundle branch block
complete heart block
sick sinoatrial node
syndrome
fibrillation
cardiac arrest
bradycardia
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Exercise 1.3
Certain Australian scientists and Australian companies have a proud
record in the development of cochlear implants. Use an Internet search
engine such as www.google.com to trace the historical development of
cochlear implants. Highlight the names of any Australian scientists,
organizations or companies when you have completed the exercise.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 1: Spare parts
33
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Senior Science
HSC Course
Stage 6
Medical technology – bionics
Part 2: Fixing a broken heart
0
20
In
r
e
to b T S
c
O EN
g
in D M
t
a
r EN
o
p
r
co A M
2
Senior Science Stage 6 HSC Course
Lifestyle chemistry
Medical technology – bionics
•
Spare parts
•
Fixing a broken heart
•
Heart to heart
•
Bone to bone
•
Breathing easy
•
Peek–a–boo
Information systems
Option
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Contents
Introduction ............................................................................... 2
Pacemakers .............................................................................. 3
The history of pacemakers ..................................................................4
Heart valves .............................................................................. 7
Demonstrating heart valves .................................................................9
Faulty valves.......................................................................................10
Artificial heart valves ..........................................................................15
Summary................................................................................. 20
Suggested answers................................................................. 21
Exercises – Part 2 ................................................................... 25
Part 2: Fixing a broken heart
1
Introduction
Part 2 covers a range of heart diseases from faulty heart valves and
enlarged hearts to hardened arteries. The medical techniques used to
correct these heart conditions range from heart valve replacement and
balloon angioplasty to heart transplants. The information in Part 2 may
make you squeamish, however, you are likely to take good care of your
heart as a result.
In this part you will be given opportunities to learn to:
•
identify that a pacemaker will produce a regular electrical pulse
•
identify the types of materials used to make pacemakers and the
properties that make these suitable for implanting in the body
•
describe the problems that can result from faulty valves in the heart
•
describe the properties of materials such as Teflon/pyrolytic carbon
that make them versatile materials for making artificial body parts,
including heart valves
In this part you will be given opportunities to:
•
identify data sources, gather and process information to outline the
historical development of pacemakers and use available evidence to
identify types of technological advances that have made their
development possible.
•
construct a simple model to demonstrate the function of valves in the
heart
•
process information to identify different types and functions of
artificial valves in the heart.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
November 2002. The most up-to-date version can be found at
http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
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Pacemakers
You learned about the effects of an irregular heartbeat in Part 1.
Years ago, nothing could be done to aid sufferers of an irregular
heartbeat. In the technological age, treating an irregular heartbeat is
quite routine.
It is likely you have heard of pacemakers. You may know someone
who has had a pacemaker implant. So, what does a pacemaker do?
Given that you have just learnt about interruptions in the heartbeat, you
probably have an idea about the function of pacemakers.
Write your ideas about the function of a pacemaker. You will review your
response after the following set of activities. If you have no idea, ask
someone their ideas about the function of a pacemaker.
_________________________________________________________
_________________________________________________________
_________________________________________________________
Listen to the Pacemaker section of the Bionics audiotape/internet audio files
then outline the structure, function and features of pacemakers by
completing the following questions.
1
Describe the structure of a pacemaker.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
2
Explain how and where a pacemaker is implanted.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 2: Fixing a broken heart
3
3
Explain the functions of a pacemaker.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
4
Explain how a pacemaker can be adjusted without surgery.
______________________________________________________
______________________________________________________
5
Describe the materials pacemakers are made of and the properties of
the materials that make them suitable for implantation.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
No answers are offered for this section to encourage you to write your
own summaries.
Turn to Exercise 2.1 to outline the need for and function of pacemakers.
Add relevant information on implants to your database or the table in
Appendix 1 from Part 1. This information will be returned with the
exercises in Part 4.
The history of pacemakers
You are about to become an expert on the evolution of pacemakers.
You need to:
•
identify data sources
•
gather, process and analyse information to outline the historical
development of pacemakers.
As you process and analyse information try to identify the technological
advances that have made development of pacemakers possible.
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Go to the www.lmpc.edu.au/science web site, then senior science. Then go
to Medical technology – bionics, click on Links and go down to Part 2.
There are a number of web sites that should help you to record information
on historical development of pacemakers on the timeline below.
If you do not have access to the Internet then try encyclopedias and medical
books in a public library as data sources.
1920
1930
1940
1950
1960
1970
1980
1990
2000
Answers are not provided for the previous activity to encourage you to
gather and process information.
Part 2: Fixing a broken heart
5
Technological advances
As you read about the development of pacemakers over time, you may
have understood that electricity had been discovered and successfully
produced for the first developments to take place. You may have also
gathered that batteries which store adequate amounts of energy to last
several years had also been invented. Other inventions and discoveries
were made, enabling the development of pacemaker models we
see today.
Match the following features of pacemakers with the technologies that
preceded their development by joining the two with a line.
Feature of pacemaker
Technological development
transistor transmitters
development of memory devices in
computers
microchips
development of material unable to
conduct electromagnetic radiation
remote control calibration and
transmission of information
development of computer chip
storage of information
development of computer sensing
equipment
sensing of information inside the
body
development of biocompatible
resins and metals
suitable coatings accepted by the
body
development of point contact
transistor
shield protecting against external
electromagnetic radiation
use of electromagnetic waves for
information transmission
Check your answers.
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Heart valves
1
Turn to page 11 of Part 1. You should have labelled four heart valves.
Repeat those labels on the following diagram of a heart.
Each valve is made of flaps of skin–like tissue. The flaps of tissue
appear to be thin and delicate, but are made of collagen, which has great
strength and flexibility. Three of the heart valves have three flaps.
The bicuspid valve (or mitral valve) has two flaps. All this means is that
tricuspid valves (with three flaps) has three spaces for blood to flow
through and the bicuspid valve has two spaces for blood flow.
2
Write three flaps or two flaps under each valve label above.
Check your answers.
Part 2: Fixing a broken heart
7
Each valve has a one–way action. The valve opens in response to
differences in pressure. The diagram below shows a valve with low
blood pressure on the ‘downstream’ side of the valve and high blood
pressure on the ‘upstream’ side of the valve. This causes the valve to
open, allowing blood to pass from an area of high pressure to
low pressure.
blood flow
low blood
pressure
high blood
pressure
open valve
Heart valve open, allowing blood to pass from an area of high pressure to low
pressure.
Once blood has passed through the valve, the distribution of pressure
changes. The downstream side of the valve now has higher pressure than
the upstream side of the valve. This puts pressure on the flaps of the
valve, causing it to close as shown below.
valve closed
high blood
pressure
low blood
pressure
blood flow
The heart valve closes with higher ‘downstream’ pressure.
You might wonder why the blood doesn’t flow backwards from high to
low pressure. The answer is the one–way valve action.
The valves are structured such that they close firmly when acted on by
high pressure from ‘downstream’, preventing the backwards flow
of blood.
If you have ever entered a shop turnstile, you will know that it will turn
one way only, allowing you into the shop. Can you exit the shop the
same way you came in? No. You generally must pass through a
checkout or another door where bags are checked. The turnstile
functions in a similar way to heart valves – allowing a one–way
passage only.
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Medical technology – bionics
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Demonstrating heart valves
Doors with hinges are usually hinged on one side only. This means they
can only open one way. These doors can be pushed to gain entry into a
room and pulled when exiting a room. The action of a one–way door is
similar to the action of a heart valve.
Find a door in your home that will only open one way. Imagine the door is a
heart valve and you are blood under high pressure.
1
Stand on the side of the door so the door opens away from you.
The door should be closed.
2
You are under high pressure and the area on the other side of the door is
under low pressure. You are only able to push on the door using your
high pressure. Push the door open and walk through to the other room.
3
Now that you are on the other side of the door, and you are still blood
under high pressure, you push the door behind you, shutting it.
4
Imagine the door had no handle. You are blood under high pressure and
all you are able to do is push, not pull. You have a natural tendency to
move from high pressure to low pressure. This means that you want to
go back through the door to where you came from which has low
pressure, but you are unable to open the door. The door only opens in
one direction – causing you to remain on that side of the door.
Well done – you just simulated the action of a heart valve. Complete the
following questions based on this activity.
1
Explain how a one–way door acts like a heart valve.
_____________________________________________________
_____________________________________________________
2
What causes a heart valve to open?
_____________________________________________________
_____________________________________________________
_____________________________________________________
3
Explain why a heart valve closes after blood has passed through the
valve.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 2: Fixing a broken heart
9
4
Explain why blood cannot flow backwards through a heart valve?
You may use the one–way door analogy to help your explanation.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
Turn to Exercise 2.2 at the back of this part to explain the function of heart
valves.
Faulty valves
Not all people are lucky enough to go through life with healthy hearts.
Unsynchronised beating is not all that can go wrong with your heart.
Faulty valves can cause symptoms such as:
•
chest pain
•
shortness of breath
•
inability to sleep
•
fatigue and an inability to carry out daily activities
•
swollen ankles
•
abnormally large abdomen.
There are two problems that can occur with heart valves.
•
Stenosis – where the valve opening becomes narrow.
•
Insufficiency or regurgitation – where the valve does not close
completely.
Stenosis
Heart valves can become calcified. This means they can become coated
in layers of calcium salts. This can be likened to coating your one–way
door with layer upon layer of paint each month of your life. The result is
a narrowing of the valve opening.
When the valve opening is smaller, less blood can pass through the
opening at any one time. This decreases the heart’s efficiency and less
blood is being pumped to the body.
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Insufficiency or regurgitation
Valves can become diseased or worn out. This results in the valves not
closing completely.
Under normal circumstances the
valve indicated in the opposite
diagram prevents the backwards
flow of blood into the atrium as the
left ventricle contracts.
atrium fills
with blood
valve closes
preventing
‘backward
blood flow’.
If the valve between the left atrium
and ventricle does not close
properly, some blood will be
forced back to the atrium instead of
the aorta. This would put extra
pressure on the atrium. The
pressure is then transferred
backwards to the lungs. This is
demonstrated in the diagram
opposite.
pressure
on lungs
less blood
pumped
to the body
faulty
valve allows
backwards
flow of blood
In this case of insufficiency, not only is the body not receiving enough
blood, the heart’s efficiency is cut down as is the lung’s efficiency.
This results in the symptoms of tiredness and shortness of breath
discussed earlier.
If you had trouble understanding this concept, the following activity may
help you.
The diagram on the following page shows traffic, representing blood,
flowing through four gates. The gates represent the four heart valves.
Use the diagram to answer the questions which follow.
Part 2: Fixing a broken heart
11
gate 1
(healthy valve)
gate 2
(calcified valve allowing
less traffic through)
gate 3
(calcified valve allowing
less traffic through)
gate 4
(healthy valve)
Traffic flowing through gates on a freeway representing blood flow through
diseased heart valves.
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Use the diagram on the previous page to write the question for the following
answers.
1
_____________________________________________________
_____________________________________________________
Gates two and three are suffering from stenosis.
2
_____________________________________________________
_____________________________________________________
Less cars appear between gates two and three because gate two is
narrow, allowing less cars through.
3
_____________________________________________________
_____________________________________________________
Around half the traffic is flowing between gates three and four as
compared to traffic flowing between gates one and two.
4
_____________________________________________________
_____________________________________________________
Less blood is leaving the heart than is entering the heart.
5
_____________________________________________________
_____________________________________________________
The person with this condition is likely to experience fatigue and
shortness of breath.
Check your answers before moving on.
Look at the diagram on the following page. The arrows indicate the flow
of traffic on a freeway, which is similar to the flow of blood. The gates
represent heart valves that only allow traffic to flow one way. One gate
is faulty, allowing traffic (blood) to flow backwards.
Use the diagram to answer the questions which follow.
Part 2: Fixing a broken heart
13
traffic flowing on a
freeway
cars spaced out, heading
in one direction
gate 1
(healthy valve
allows traffic
one way only)
gate 2
(healthy valve
allows traffic
one way only)
cars bunched
up facing both
directions
gate 3
(diseased valve allows
traffic to flow backwards)
gate 4
(healthy valve allows
traffic one way only)
less traffic is
flowing
Traffic flowing through gates on a freeway representing blood flow through
diseased heart valves.
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Refer to the diagram on the previous page to answer the following
questions.
6
What do the backwards arrows indicate between gates 3 and 4?
_____________________________________________________
7
What is happening to blood flow between gates 2 and 4?
_____________________________________________________
_____________________________________________________
8
Explain why traffic is flowing both ways between gates 3 and 4 and
gates 2 and 3?
_____________________________________________________
_____________________________________________________
_____________________________________________________
9
Which condition is gate 3 suffering from – stenosis or insufficiency?
_____________________________________________________
10 Which gate experiences excess pressure as a result of gate 3 being
faulty? Explain your choice.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
Turn to Exercise 2.3 at the back of this part to create a webpage explaining
heart valve conditions.
Artificial heart valves
You might think the replacement of faulty heart valves would be close to
impossible. In reality, heart valve replacement is a relatively common
procedure, with 200 000 heart valve replacements each year.
Go to the www.lmpc.edu.au/science web site, then senior science. Then go
to Medical technology – bionics, click on Links and go down to Part 2.
There are a number of web sites that should help you to record information
on the different types and functions of artificial heart valves. Describe the
properties of materials used that make them suitable for implanting in the
body. The following two pages are blank for you to record information.
Part 2: Fixing a broken heart
15
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Use the information you have read and recorded to attempt the questions
on the next three pages. If you find a question too difficult go on to the
other questions. Use key words in the questions you had difficulty with
to search out further information on the Internet that could help
with answers.
Part 2: Fixing a broken heart
17
1
What major development has allowed heart valve surgery?
_____________________________________________________
2
What do pigs, bioprosthetic valves and humans have in common?
_____________________________________________________
_____________________________________________________
3
Identify (recognise and name) three different types of artificial heart
valves by adding the labels ball valve, tilting disk valve and bileaflet
valve to the diagrams below.
Valve type
4
Diagram
List five materials currently used in artificial heart valves in the table
below. Gather your information from web sites.
Materials currently used in replacement heart valves
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Durable
Thromboresistant
Strong
Material
Smooth
From the following qualities, match the material from the above
question to the qualities listed below that make it useful as a valve
implant. The first one has been done for you as a guide.
(Each material may have more than one quality. You may need to
draw your own conclusions on the qualities each material must have
based on the evidence available.)
Light weight
5
pyrolytic carbon
6
Explain two problems associated with some heart valve designs and
the materials used.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
Turn to Exercise 2.4 at the back of this part to address questions on
replacement heart valves.
Add relevant information on implants to your database or the table in
Appendix 1 from Part 1. This information will be returned with the
exercises in Part 4.
Part 2: Fixing a broken heart
19
Summary
Use the letters below to begin 20 sentences which will help you
remember information in this part. The object of this activity is to create
about a single page summary that you can revise before an exam.
a ________________________________________________________
b ________________________________________________________
c ________________________________________________________
d ________________________________________________________
e ________________________________________________________
f_________________________________________________________
g ________________________________________________________
h ________________________________________________________
i_________________________________________________________
j_________________________________________________________
k ________________________________________________________
l_________________________________________________________
m________________________________________________________
n ________________________________________________________
o ________________________________________________________
p ________________________________________________________
r_________________________________________________________
s ________________________________________________________
t_________________________________________________________
u ________________________________________________________
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Suggested answers
Technological advances
Feature of pacemaker
Technological development
transistor transmitters
development of point contact transistor
microchips
development of computer chip
remote control calibration and
transmission of information
use of electromagnetic waves for
information transmission
storage of information
development of memory devices in
computers
sensing of information inside the body
development of computer sensing
equipment
suitable coatings accepted by the body
development of biocompatible resins and
metals
shield protecting against external
electromagnetic radiation
development of material unable to conduct
electromagnetic radiation
Heart valves
pulmonic valve
three flaps
tricuspid valve
three flaps
Part 2: Fixing a broken heart
bicuspid valve
two flaps
aortic valve
three flaps
21
Demonstrating heart valves
1
A one–way door can only open in one direction – heart valves also
open in one direction only.
2
A heart valve opens due to the pushing action of blood attempting to
move from high pressure to low pressure.
3
After blood has passed through the valve, the areas of high and low
pressure are reversed. When high pressure acts on the ‘downstream’
end of the heart valve, it causes it to close.
4
Blood cannot flow backwards through a heart valve because the
pressure of the blood flowing backwards onto the valve flaps causes
them to close, like the pushing action on the back of a door. This
closure prevents blood from flowing backwards.
Faulty valves
1
What are gates two and three suffering from in terms of diseased
heart valves? Other answers are acceptable.
2
Explain the traffic conditions between gates two and three in terms
of diseased heart valves. Other answers are acceptable.
3
How much traffic is flowing between gates three and four as
compared to traffic flowing between gates one and two? Other
answers are acceptable.
4
Compare the amount of blood entering the heart (freeway) to the
blood leaving the heart. Other answers are acceptable.
5
If a person has a heart with diseased valves as shown in the diagram,
explain two symptoms they are likely to experience. Other answers
are acceptable.
6
The backwards arrows between gates 3 and 4 indicate blood flowing
in both directions.
7
Blood is flowing in both directions between gates 2 and 4.
8
Blood is flowing both ways between gates 2 and 3 and 3 and 4
because gate 3 is faulty, allowing blood to move backwards through
the gate.
9
Gate 3 is suffering from insufficiency.
10 The diagram shows traffic banking up to gate 2. Gate 2 is
experiencing excess pressure as a result of gate 3 not functioning
properly.
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Artificial heart valves
1
The heart and lung machine which allows the heart to stop
functioning while keeping the patient alive during the surgery, has
allowed the replacement of heart valves.
2
Bioprosthetic valves from pigs have been implanted as replacement
heart valves in humans.
3
Valve type
Diagram
ball valve
bileaflet valve
tilting disc valve
4
Materials currently used in replacement heart valves
pyrolytic carbon
silicone rubber ball with 2% barium sulfate
cage–stellite alloy No. 21
sewing ring knitted teflon and polypropylene cloth
titanium
isotropic pyrolitic carbon – Uglesitall
cobalt/chrome alloy
knitted polyester
Part 2: Fixing a broken heart
23
Durable
Thromboresistant
Strong
Smooth
Material
Light weight
5
pyrolytic carbon
Silicone rubber ball with 2%
barium sulfate
Cage–Stellite alloy No. 21
Knitted Teflon and
polypropylene cloth
titanium
isotropic pyrolitic carbon
cobalt/chrome alloy
knitted polyester
6
Problems associated with some replacement heart valves are:
knitted Teflon could fray and cause blood clots to form;
silicone balls can swell and get stuck inside the valve;
valves that are sutured into place can cause swelling,
infections and blood clotting.
Other answers are acceptable.
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Exercises - Part 2
Exercises 2.1 to 2.4
Name: _________________________________
Exercise 2.1
Imagine you are 47 years old. You have been experiencing shortness of
breath, seemingly constant exhaustion and a fluttering feeling in your
chest. You are referred to a cardiac specialist. The cardiac specialist
tests the electrical signals within your heart and recommends the
implantation of a pacemaker. You listen to her explanation about the
procedure.
In two paragraphs or less, write a concise explanation of a pacemaker, its
parts, installation, function, length of surgery and adjustments after
surgery that the cardiac specialist is likely to tell you.
Remember to think like a cardiac specialist as you are writing your
explanation. Use the terms they would when dealing with a patient and
remember to explain all the points outlined in the previous paragraph.
Room for your answer continues on the following page.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 2: Fixing a broken heart
25
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Exercise 2.2
Heart valves have a specific function. Their structure is closely related to
their function.
In one paragraph, explain their structure, how heart valves work and
relate this to their function. You may use diagrams in the margin to help
with your answer.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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Exercise 2.3
Imagine you are a patient experiencing tiredness and shortness of breath.
Your doctor explains you are likely to have faulty heart valves, although
he doesn’t have time to explain it to you.
You go home and search the Internet to find out what could be wrong
with your heart valves. Imagine that you find a webpage that fully
explains two problems associated with faulty heart valves that you could
have. Use the space provided below to create a web page that you think
fully explains the two possible heart valve conditions. Be as creative and
innovative as you like. This page has been left blank for this purpose.
Part 2: Fixing a broken heart
27
Exercise 2.4
1
Draw an example of a replacement heart valve below.
2
Explain two problems associated with replacement heart valves
encountered by doctors through history.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
3
State three materials currently used in heart valves and explain why
these materials are suitable for use in transplants.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Add relevant information on implants to your database or the table in
Appendix 1 from Part 1. This information will be returned with the
exercises in Part 4.
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Senior Science
HSC Course
Stage 6
Medical technology – bionics
Part 3: Heart to heart
0
20
I
er
b
to T S
c
O EN
g
in D M
t
a
r EN
o
p
or AM
c
n
2
Senior Science Stage 6 HSC Course
Lifestyle chemistry
Medical technology – bionics
•
Spare parts
•
Fixing a broken heart
•
Heart to heart
•
Bone to bone
•
Breathing easy
•
Peek–a–boo
Information systems
Option
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Contents
Introduction................................................................................ 2
Heart transplants ....................................................................... 3
Atherosclerosis.......................................................................... 6
Reducing the risk..................................................................................8
Techniques for treating atherosclerosis ..............................................9
Optional activity – the red bullet........................................................ 12
The skeletal system................................................................. 14
Calcium compounds in bones........................................................... 16
Summary ................................................................................. 17
Suggested answers................................................................. 21
Exercises – Part 3 ................................................................... 25
Part 3: Heart to heart
1
Introduction
Part 3 covers build up and elimination of plaque in the blood circulation
system then introduces you to the structure of bones by investigating
those in chicken limbs.
In this part you will be given opportunities to learn to:
•
describe and explain the effects of a build up of plaque on the walls
of major arteries and veins on the blood flow to and from the heart
•
discuss ways in which plaque can be eliminated or altered to ease
blood flow
•
identify the role of the skeletal system particularly in relation to
maintaining an upright stance and protecting vital organs
In this part you will be given opportunities to:
•
gather information from secondary sources on techniques used
including angioplasty, to ease blood flow to and from the heart and
in blood vessels, when there has been a build up of plaque
•
gather, process and analyse information to outline areas of current
research in heart transplants and/or artificial hearts and their impact
on society
•
perform a first hand investigation to remove calcium compounds
from chicken bones to examine the flexible nature of bones.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
November 2002. The most up-to-date version can be foundat
http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
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Heart transplants
Before beginning Part 3, turn to the experiment on page 16 where you place
a chicken bone in vinegar. You will need at least three days to complete this
experiment. It is strongly suggested you start this experiment now, as your
results and conclusions will be sent in with the exercises from this part.
In some cases, there is more wrong with a person’s heart than an irregular
heartbeat, faulty valves or artery plaque. Possible heart problems are:
•
cardiomyopathy (any disease of heart muscle; usually causes an
enlarged heart)
•
autoimmune disease (in which the body’s immune system attacks
the heart).
Heart transplants are often the only option for some sufferers of heart
disease. In the future artificial hearts may replace heart transplants.
You are about to gather information to help you outline areas of current
research with regards to heart transplants and artificial hearts.
Go to the www.lmpc.edu.au/science web site, then senior science. Then go
to Medical technology – bionics, click on Links and go down to Part 3.
There are a number of web sites that should help you to record information
on current research into heart transplants and artificial hearts..
Regard current research as research carried out in the last two years.
Check that the web site information has been produced or updated in the last
two years.
If you do not have access to the Internet then try encyclopedias and medical
books in a public library as data sources. Record the date of publication and
when the information was last revised. The next page is available for you to
record the information.
Part 3: Heart to heart
3
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Social implications of heart transplants
The development of medical procedures that allow heart transplants to
take place has several impacts in society.
•
People with heart disease can live a longer life – this contributes to
an aging population.
•
People awaiting heart transplants can wait years for a transplant due
to a lack of donors. This can have a significant impact on the
recipient, caregivers and hospitals which attempt to keep the person
alive after their own heart ceases to function.
•
Heart transplant recipients experience emotional distress at being
called into hospital to receive a transplant and the donor heart is
found to be damaged and not viable for transplantation.
•
Ethical, moral and religious implications argue for and against
replacing body parts to extend the lives of people who would
otherwise die.
•
Patients may increase their susceptibility to other life threatening
diseases as a result of a heart transplant by taking immune
suppressing drugs which minimise the rejection of transplanted
tissue.
•
Upon obtaining a driver’s license, people must choose to be an organ
donor or not.
•
Families of people who die suddenly are faced with organ donation
decisions as they are coming to grips with the tragedy.
•
Families of brain dead victims, whose heart and lungs are
functioning are faced with organ donation decisions when the person
still appears to be alive. (Organs are often removed while the body
is still functioning to optimise the recipients’ chances of survival.)
•
Removal of organs such as a beating heart from a brain dead person
has emotional impacts on nurses and medical staff as the person is
technically still alive.
Turn to Exercise 3.1 at the back of this part to summarise current research in
heart transplants and artificial hearts and their impacts on society.
Part 3: Heart to heart
5
Atherosclerosis
Atherosclerosis is the building up on the innermost layer of the artery
wall of fatty deposits which harden to form plaque. A person suffering
from a heart attack is actually suffering from a lack of blood to the heart
muscles themselves. All muscles need a constant supply of blood to
function and heart muscles are no exception. Arteries on the surface of
the heart supply life–giving oxygen and glucose to the heart itself,
allowing it to pump, thus keeping you alive.
When the arteries supplying blood to heart muscles become blocked, the
heart muscles no longer have the requirements to function. The heart
muscle cells can die rapidly and, without intervention, the person will
die. Arteries leading away from the heart can also become blocked with
fatty residue. What would you expect to happen if blood is prevented
from flowing out of the heart as it is pumping? The thought isn’t pretty
is it!
The question then is – what causes blocking of arteries and what can be
done to treat and prevent it?
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Listen to the Coronary artery disease section of the Bionics
audiotape/internet audio files. The information contained in the audiotape
matches the diagrams below. Complete the table.
1
2
3
4
5
Answers are not supplied for this audio activity to encourage you to
complete the activity.
Part 3: Heart to heart
7
By the time a person notices symptoms of atherosclerosis, such as
tiredness and shortness of breath, it has advanced to the stage where it is
almost life threatening. So, how can atherosclerosis be avoided?
Reducing the risk
Your blood carries the two forms of lipoproteins that are associated with
cholesterol. Low density lipoproteins (LDL) transports cholesterol
around the body in the blood stream. LDL is the form of cholesterol
which is deposited on artery walls, forming artery plaque. LDL is often
referred to as bad cholesterol.
High density lipoproteins (HDL) is good cholesterol. HDL assists in
removing LDL from artery walls, delivering it to the liver for removal.
Research has shown that high levels of HDL are just as important as low
levels of LDL in the blood for reducing the risk of atherosclerosis.
The question then is – how can one maintain low levels of LDL and
increase HDL in the blood? The answer lies in diet.
A diet high in complex carbohydrates, vitamin rich fruits and vegetables
and low in fats is important in maintaining low LDL and high HDL
levels. Such a diet also offers numerous other health benefits. In fact a
healthy diet from a young age almost ensures against the formation of
artery plaque. What you eat will flow through your blood. If you eat
fried, fatty foods, the fat will be absorbed into your blood stream and the
cholesterol may be deposited on your artery walls – even in childhood.
Lifestyle also plays an important role in reducing the risk of
atherosclerosis. Smokers more than double their risk of atherosclerosis
and passive smokers (those who breathe in second–hand smoke) increase
their risk of atherosclerosis by 20%. Regular exercise and low stress
levels helps keep the body healthy, reducing the risks associated with
hardening of the arteries.
State four ways you can reduce the risk of atherosclerosis.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Check your answers.
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Techniques for treating
atherosclerosis
The best way to prevent or minimise atherosclerosis is by wise lifestyle
choices. There are many things one can change in life – where you live,
what work you do, who you associate with, how you spend your time,
etc. However, the body you are born with cannot be changed. That body
is your body for life. The emphasis by many in society may be on the
external appearance of your body but what really counts is the condition
of your internal parts. Especially important is the condition of the
muscles that make up the walls of your arteries. If the arteries have
deposits of plaque they cannot do their job as effectively. Prevention of
atherosclerosis by making wise lifestyle choices is the best approach.
If prevention fails and a person has access to modern technology there
are several techniques for treating atherosclerosis. Seven of them are:
•
atherectomy
•
balloon angioplasty
•
bypass surgery
•
cardiac catheterization
•
laser angioplasty
•
stents
•
thrombectomy.
If you know the meanings of parts of scientific, technical and medical
terms you can often work out what long words or terms mean.
For example–ectomy on the end of a word refers to removal of the part at
the start of the word. You should be able to work out what is removed in
an appendicectomy operation.
Angioplasty refers to repair of a blood vessel. You should be able to
work out what is used to repair a blood vessel in balloon angioplasty and
in laser angioplasty.
The table on the next page requires you to label seven diagrams. Each of
these diagrams represents one of the techniques that could be used to treat
atherosclerosis. By carefully looking at each diagram and reading the notes,
you should be able to select a suitable label from the list above.
After you have labeled the seven diagrams check your answers.
Part 3: Heart to heart
9
artery
dye showing
artery width
artery
balloon is blown
up repeatedly,
pressing plaque
against artery
walls
plaque
catheter inserted
into artery
catheter injecting
dye into artery
rotating blade
breaks artery plaque
into microscopic
particles
stent in place
in artery, holding
artery open,
restoring blood
flow
plaque
blood
artery
artery
plaque
pushed to the
artery walls
catheter
laser vapourises
plaque in a
blocked artery
to restore
blood flow
thrombus or
blood clot
is removed
to restore
blood flow
artery
plaque
artery
catheter
vein is used to
bypass the
clogged artery,
restoring blood
flow
hardened
artery
with little
blood flow
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Bypass surgery
Laser angioplasty
Thrombectomy
Atherectomy
Stents
Statement
Balloon angioplasty
Tick the procedure described by each of the following statements.
The first one has been done for you as a guide.
Cardiac catheterisation
1
a procedure to detect the severity of
atherosclerosis
a blade is used to cut away plaque
from artery walls
a clot is removed from an artery,
restoring blood flow
a balloon on a catheter is expanded
in an artery
blood is directed around the blocked
artery
a hole is made in the centre of a
plaque blockage
dye is injected into the
affected artery
wire coil holds the
artery open
artery plaque is flattened against
artery walls
this method is only used when
angioplasty fails
a high speed blade rotates, removing
plaque
used when one or two coronary
arteries are affected
2
Explain why arteries affected by atherosclerosis should be treated.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
Turn to Exercise 3.2 at the back of this part to outline three procedures
which restores blood flow in arteries affected by atherosclerosis.
Part 3: Heart to heart
11
Optional activity – the red bullet
Did you know that hardening of the arteries and strokes are often
related?
For each of the diagrams below, colour the blood in the center of the artery
in red, the plaque yellow and the artery wall in pink.
A typical artery with plaque
lining the artery walls.
blood
artery
plaque
A physiological response to
stress is artery contraction.
Emotional stress causes greater
artery contraction than physical
exercise. Contraction causes
the plaque to be crunched,
allowing cracks to form in the
plaque’s hard seal.
12
crack in plaque
contracted artery
plaque
The cracks allow soft fat to
ooze out from under the hard
fatty seal like egg white oozes
out of a cracked egg. The soft
fat can then travel down
stream, adding to artery plaque
in another part of the body.
soft fat oozing
into the blood
stream from
cracked
plaque
A blood clot forms at the
cracked plaque site sealing the
crack. You are familiar with
blood clotting when you cut
your skin. If the blood did not
clot, forming a seal, you could
bleed to death, even from a
small skin cut.
blood clot
sealing
plaque
crack
blood
plaque
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The blood clot has the potential
to break away with the force of
blood flow, traveling down
stream. The blood clot then
has the potential to completely
clog smaller veins and
capillaries, halting blood flow
and starving cells of vital
oxygen and nutrients.
A blood clot to the brain can block blood flow to brain cells, causing one
form of stroke, and possibly shutting the brain down. This can kill
the person.
Blood may be thinned with aspirin, minimising the danger of blood clots
and potential strokes.
Procedures that involve insertion of catheters into arteries for
investigatory or artery opening purposes can break away plaque on artery
walls, causing cracks and subsequent blood clots, thus increasing the
chances of stroke.
Part 3: Heart to heart
13
The skeletal system
The skeleton protects many of the internal organs. For example, the
brain is encased in the skull, the heart and lungs are surrounded by the rib
cage and the spinal cord runs within the canal formed by the vertebrae
(backbones).
Colour the skull, rib cage and spine in three different colours on the skeleton
draw below. This will highlight the bones that protect vital organs.
Human skeleton.
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The human skeletal system also plays a vital role in maintaining an
upright stance. Bones are strong for this purpose.
Reconstruct the following sentence.
an protects The system upright skeletal and vital maintains organs stance.
_________________________________________________________
_________________________________________________________
Check your answers.
The diagram below shows the different types of tissue inside the longest
bone in the human body (the femur).
The anatomy of a bone.
Bones are living body parts. They are made of cells, just as your skin,
lungs and heart are made of cells. Your bones store many mineral salts
containing calcium, phosphorus, sodium and potassium. The above
diagram shows ‘spongy’ bone with pores in the bone at each end and a
hollow centre containing bone marrow.
Part 3: Heart to heart
15
The strength of different parts of bones differs due to their structure.
The cancellous or spongy bone at the ends of bones is typically
surrounded by cartilage. The cartilage itself absorbs impacts as it is very
flexible. The cancellous bone under the cartilage is more rigid than the
cartilage, but is able to absorb greater shocks than the diaphysis (the long
section of bone), which is even more rigid.
This means that, in general, the ends of bones (the epiphysis) are more
able to absorb shocks than the straighter section of bone.
Indicate the shock absorbing abilities of cancellous bone and the diaphysis
by labelling the diagram on the previous page.
Calcium compounds in bones
Bones are made of collagen (a very strong, flexible protein) and calcium
phosphate salt which hardens the bone.
You may have the idea that bones are solid, inflexible structures that
break or shatter under great stress. You may change you ideas after the
following activity.
Aim
•
To remove calcium compounds from a chicken bone.
•
To examine the flexible nature of bones.
You will need:
•
an uncooked chicken bone, for example, a chicken leg (with meat
removed)
•
white vinegar
•
a glass, glass jar or container large enough for your chicken bone.
Method
1
Observe the solid structure of the bone prior to the experiment by
attempting to bend the bone.
2
Place the chicken bone in the glass, jar or container.
3
Completely submerge the bone in vinegar.
Continue this experiment in Exercise 3.3 at the back of this part.
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Summary
You have an opportunity to reflect on your learning while reviewing the
information you have gained in Parts 1 to 3.
Enjoyment
Each activity from Parts 1 to 3 are listed below.
1
Tick the boxes on the left to indicate the activities you enjoyed.
2
Colour in the boxes on the right to indicate the amount of information
you feel you absorbed from each activity outlined. An example has
been done for you as a guide.
Activity
Percent learned
0%
50%
100%
External biomedical devices – information
on audiotape/internet audio file.
External biomedical devices – information
on audiotape/internet audio file.
Creating a timeline of the development of
pacemakers.
Adding information on biomedical
implants to a table.
Labeling the heart from the audio and
answering true/false questions.
Carrying out an investigation on your
pulse rate.
Part 3: Heart to heart
17
Answering questions on how the heart
beats.
Listening to a person’s heartbeat.
Explaining abnormal heartbeats from a
doctor’s perspective.
Summarising different conditions
responsible for an irregular heartbeat.
Gathering information on pacemakers
from the audio.
Explaining pacemakers from a doctors
perspective.
Extracting information on the history of
pacemakers from the Internet.
Matching information on technological
developments aiding pacemaker use.
Labelling the different heart valves in the
heart.
Demonstrating the action of heart valves
by walking through a door–way.
Explaining the function of heart valves.
Linking information on cars on highways
to blood flow through heart valves.
18
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Designing a webpage explaining different
heart valve conditions.
Researching and reporting on artificial
heart valves from Internet information.
Quickly scanning information on research
into heart transplants.
Presenting brief summaries on research
into heart transplants and artificial hearts.
Recording information on atherosclerosis
from the audio next to diagrams.
Learning how to reduce the risk of
atherosclerosis.
Labeling a table showing the techniques
used to treat atherosclerosis
Colouring in diagrams associated with the
red bullet (strokes) – optional activity.
Skeletal system – colouring in; sentence
reconstruction; and labeling diagram.
Removing calcium compounds from a
chicken bone.
You probably didn’t realise all the activities you have carried out in this
module. The amount you shaded in the right column should indicate the
knowledge you have gained so far in Medical technology – bionics.
You can be the judge of the amount you have learned – and the amount
of revision you require.
Part 3: Heart to heart
19
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Suggested answers
Reducing the risk
The risk of atherosclerosis can be significantly reduced with: a diet high
in complex carbohydrates, fruits and vegetables and low in fat; regular
exercise; low stress levels; and not smoking.
Techniques for treating atherosclerosis
artery
dye showing
artery width
artery
balloon is blown
up repeatedly,
pressing plaque
against artery
walls
plaque
catheter inserted
into artery
catheter injecting
dye into artery
Cardiac catheterisation
Balloon angioplasty
rotating blade
breaks artery plaque
into microscopic
particles
stent in place
in artery, holding
artery open,
restoring blood
flow
plaque
blood
artery
Stents
Part 3: Heart to heart
artery
plaque
pushed to the
artery walls
catheter
Atherectomy
21
laser vapourises
plaque in a
blocked artery
to restore
blood flow
thrombus or
blood clot
is removed
to restore
blood flow
artery
plaque
catheter
artery
Thrombectomy
Laser angioplasty
vein is used to
bypass the
clogged artery,
restoring blood
flow
hardened
artery
with little
blood flow
Bypass surgery
22
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a blade is used to cut away plaque
from artery walls
✓
a clot is removed from an artery,
restoring blood flow
✓
a balloon on a catheter is expanded
in an artery
✓
blood is directed around the blocked
artery
✓
a hole is made in the centre of a
plaque blockage
dye is injected into the affected artery
✓
✓
✓
wire coil holds the artery open
artery plaque is flattened against
artery walls
✓
this method is only used when
angioplasty fails
✓
a high speed blade rotates, removing
plaque
used when one or two coronary
arteries are affected
2
Bypass surgery
Laser angioplasty
Thrombectomy
Atherectomy
✓
Stents
a procedure to detect the severity of
atherosclerosis
Balloon angioplasty
Statement
Cardiac catheterisation
Detecting and treating atherosclerosis
✓
✓
Arteries affected by atherosclerosis should be treated or the
condition will compound, eventually blocking blood flow to and
from the heart. Other answers are acceptable.
The skeletal system
The skeletal system maintains an upright stance and protects vital organs.
Part 3: Heart to heart
23
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Exercises - Part 3
Exercises 3.1 to 3.3
Name: _________________________________
Exercise 3.1
Choose two areas of current research into heart transplants and two areas
of current research into artificial hearts. For each research area:
•
explain the research
•
explain the possible implications of the research with regards to heart
transplants or artificial hearts
•
explain how you think the research could impact on society (this can
be the same for many areas of research).
Research
Part 3: Heart to heart
Implications
Impact on society
25
Exercise 3.2
Draw an example of and explain, in your own words, three different
procedures which restore blood flow in arteries affected by
atherosclerosis.
1
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
2
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
3
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
26
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Exercise 3.3
This experiment is continued from Calcium compounds in bones on
page 16.
1
Draw a diagram of the chicken bone submerged in vinegar.
The space provided indicates the size of the diagram required.
Use pencil and label parts of the diagram.
2
Leave the bone in the vinegar for at least three days.
Is vinegar acid or alkaline?
_____________________________________________________
Can this substance damage your skin? What other things may be
damaged with this substance?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Explain how will you ensure this substance is handled carefully to
reduce possible hazards.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 3: Heart to heart
27
Given that vinegar can be dangerous, how will you dispose of the
used vinegar? Give a reason for your choice.
______________________________________________________
______________________________________________________
______________________________________________________
3
After at least three days remove the chicken bone from the vinegar
and soak it in water for three hours.
4
Observe the flexibility of the bone, comparing it to its flexibility
before immersion in the vinegar. Write a sentence about any change
in flexibility in the next (results) section.
Results
Draw the bone as bent as you can make it, or take a photograph and glue
in the space provided.
Continued on the next page.
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Scientific testing of materials can be destructive or non–destructive.
Destructive testing causes a chemical reaction to take place, which alters
the chemical nature of the specimen. This type of testing is difficult or
impossible to reverse. Non–destructive testing allows data collection
without changing the chemical components of the specimen. Such tests
are often observation based.
Which type of testing did you just carry out on the chicken bone?
Explain your answer.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
State the non–destructive tests you did on the chicken bone before and
after placing it into vinegar. Explain why these tests are non–destructive.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Every substance has physical and chemical properties. Physical
properties can be easily observed on the substance by itself, however
understanding the chemical properties of a substance requires testing
with other substances.
State the different types of results you gathered from destructive and
non–destructive testing. It may help you to refer to the physical and
chemical properties of the chicken bone in your answer.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 3: Heart to heart
29
Conclusion
Given that bones are made of collagen and calcium compounds, which of
these were removed from the bone with the use of vinegar? Use your
observations of your chicken bone to help explain your answer.
You may also refer to page 16 to help explain your answer.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Explain how this experiment demonstrates the flexible nature of bones.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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Senior Science
HSC Course
Stage 6
Medical technology – bionics
Part 4: Bone to bone
0
20
In
r
e
to b T S
c
O EN
g
in D M
t
a
r EN
o
p
r
co A M
2
Senior Science Stage 6 HSC Course
Lifestyle chemistry
Medical technology – bionics
•
Spare parts
•
Fixing a broken heart
•
Heart to heart
•
Bone to bone
•
Breathing easy
•
Peek–a–boo
Information systems
Option
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Contents
Introduction ............................................................................... 2
Synovial joints ........................................................................... 4
Joint structures .....................................................................................4
Joint movement ....................................................................................5
Synovial joint classification ..................................................................7
Artificial joints .......................................................................... 13
Silicone joints......................................................................................13
Large artificial joints ...........................................................................15
Life of replacement joints ...................................................................18
Joint fixation........................................................................................19
Summary................................................................................. 21
Appendix ................................................................................. 23
Suggested answers................................................................. 25
Exercises – Part 4 ................................................................... 31
Part 4: Bone to bone
1
Introduction
In Part 4, you will be given opportunities to learn to recognise different
types of joints, what artificial joints are made from and where they are
placed in the body. You will learn how the implants are attached to
bones and current research involving the life of artificial joints.
In this part you will be given opportunities to learn to:
•
describe the different types of synovial joints as
–
ball and socket
–
hinge
–
double hinge
–
sliding
–
pivot
and identify their location
•
describe the role of cartilage and synovial joint fluid in the operation
of joints
•
identify the properties of silicone that make it suitable for use in
bionics
•
explain why silicone joints would be suitable substitutes for small
joints in the fingers and toes that bear little force
•
describe the properties that make ultrahigh molecular weight
polyethylene (UHMWPE) a suitable alternative to cartilage
surrounding a ball and socket joint in terms of its
•
2
–
biocompatibility with surrounding tissue
–
low friction
–
durability
explain why artificial joints have the articulating ends covered in
polyethylene
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•
describe the properties of the materials including ‘superalloy’ that
make a ball and stem for the bone components of a large joint
including:
–
high strength
–
low weight
–
good compatibility with body tissue
–
inertness
•
identify that artificial implants can be either cemented or
uncemented into place
•
describe the properties of the cement that is used in implants and
discuss how an uncemented implant forms a bond with the bone.
In this part you will be given opportunities to:
•
perform an investigation to examine the relationship between
cartilage, muscle, tendon and bone in an animal limb
•
perform an investigation to demonstrate the different types of joints
and the range of movements they allow
•
process secondary information to compare the shock absorbing
capabilities of different parts of bones
•
plan, choose equipment or resources for and perform a first–hand
investigation to demonstrate the properties of silicone such as acid
resistance, flexibility and imperviousness to water that make it
suitable for use in bionics
•
analyse secondary information to compare the strength of UHMWPE
and ‘superalloy’ metal.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
November 2002. The most up-to-date version can be found at
http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
Part 4: Bone to bone
3
Synovial joints
Joints allow our body to move. This body movement is produced by
muscle action across a joint.
The definition of a joint is the place where two or more bones meet.
Joints can be classified according to the structure and the material that
connects the joints or the degree of movement that occurs at that joint.
Joint structures
Ligaments
Tough bands of collagen ( a very strong, flexible substance) which hold
a joint together by joining bones on one side of a joint to bones on the
other side. They act like strong rubber bands, holding bone ends together
at the joint. They prevent dislocation but stretch slightly to allow the
bones to move.
Tendons
Tough, rope–like strands which connect muscle to bone.
Synovial fluid
The slippery fluid which lubricates movable joints. It is secreted by the
synovial membrane which is a lining on the inner surface of the
joint capsule.
Cartilage
A rubbery substance which is used to support and protect the body from
shocks and impacts. The ends of the bone are covered with cartilage to
make a smooth, flexible joint.
Joints about which bones move are classified as synovial joints.
These joints contain synovial fluid for joint lubrication.
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Write the joint structure described by the statements below in the space
provided.
1
A rubbery substance covering ends of bones.
__________________
2
‘Rubber bands’ that hold bones together.
__________________
3
Very strong flexible substance.
__________________
4
Connects muscle to bone.
__________________
5
Protects and supports bones against impacts.
__________________
6
Lining on the inner surface of a joint capsule.
__________________
7
Slippery fluid lubricating a joint.
__________________
8
Prevents dislocation of bones.
__________________
Check your answers.
Turn to Exercise 4.1 at the back of this part to examine joint structures in
chicken limbs.
Joint movement
Features of synovial joints are shown in the diagram below.
Synovial joint.
Part 4: Bone to bone
5
Refer to the diagram on the previous page to complete the sentences that
describe the features of synovial joints.
1
The ________________ ________________ encloses the joint.
2
The ________________ membrane lines the joint capsule. It secretes
synovial fluid into the cavity.
3
________________ ________________ fills the joint cavity.
It lubricates the joint and provides nutrients.
4
________________ ________________ covers the end of the bones in
a joint. It is smooth, shiny and white. Articular cartilage reduces the
friction between the bones in a joint.
Check your answers.
Factors affecting movement
Each type of synovial joint has a different range of movements.
Movements are mainly determined by the shape of the bones at the joint.
Other factors that influence movement are:
•
the flexibility or elasticity of ligaments and tendons. Tendons
connect muscles to bones.
•
the strength and length of muscles around a joint
•
the presence of synovial fluid.
1
The degree and kind of movement in each joint varies. List three things
that may limit the range of movement in a joint.
_____________________________________________________
_____________________________________________________
Many people have ligament reconstruction operations as a result of
sporting injuries. The operations involve connecting the bones together
again using the existing ligament or grafting a piece of tendon.
The most common ligament reconstructions are for the shoulder and
knee.
2
Which sports do you think are likely to injure the knee and shoulder?
______________________________________________________
______________________________________________________
Check your answers.
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Synovial joint classification
Synovial joints differ according to the shapes of the ends of the bones of
different joints. There are several types of synovial joints:
•
ball and socket joint eg. in the shoulder
•
hinge joint eg. in the elbow
•
sliding joint eg. in the backbone
•
pivot joint eg. in the neck
•
double hinge joint eg. in the hand
•
saddle joint eg. in the thumb.
Ball and socket joint
In ball and socket joints, the end of one bone is shaped like a ball.
It fits the end of another bone that is shaped like a cup or socket.
An example is where the femur joins the pelvis at the hip. Examine the
diagram that follows. You can see the end of the femur is shaped like a
ball. The pelvis has a socket (or cup) where the femur joins the hip.
Ba
ll and socket hip joint.
1
Do you have a mortar and pestle that you use in the kitchen? If so,
move the pestle around in the mortar. Another way to demonstrate a
ball and socket joint is to make a fist with one hand and a cup shape
with the other. Place the ball (fist) in to the socket (cupped hand).
Now rotate your fist.
Part 4: Bone to bone
7
This will give you an idea of the sort of movements that a ball and
socket joint can perform.
2
Move your arm at the shoulder and your leg at the hip. Tick the
movements you can do with the joints below.
3
Movement
Shoulder
Hip
lift limb forward
lift limb backwards
lift limb to the side
lift to the opposite side
rotate the limb in a circular motion
You should have found that a ball and socket joint allows the following
range of movements:
•
bending
•
straightening
•
movement away from the body
•
movement towards the body
•
rotation movements
Hinge joint
Hinge joints are another type of synovial joint. They occur where the
extremities of two joining bones fit like a hinge.
Examine the following diagram. This shows the elbow, which is an
example of a hinge joint. The bone in the upper arm (humerus) joins a
bone in the lower arm (ulna).
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Hinge joint in the elbow.
Bend your elbow.
Can you move your forearm from side to side from the elbow?
Based on the information above, why do you think this is?
_________________________________________________________
_________________________________________________________
Check your answer.
Sliding joint
Sliding joints in the spine.
Part 4: Bone to bone
9
Sliding joints only allow movement from side to side or back to front.
The joints between the ribs and the vertebra joints are sliding joints.
This type of joint is shown in the diagram above. You can see that each
of the adjoining vertebrae is separated by a disc.
Another example of a sliding joint is found in the wrist.
1
Stand up straight. Can you bend from side to side? How far down your
leg can you reach?
_____________________________________________________
2
Stand up straight. Can you bend backwards very far?
_____________________________________________________
Move your back to see the range of movements that are possible.
Can you bend further in a forwards direction than a backwards? Explain
why this is so. Look at the diagram of the vertebrae to help explain your
answer.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Check your answer.
Pivot joint
Pivot joint in the neck.
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A pivot joint is only capable of rotation. Look at the diagram on the
previous page, which shows the atlas and axis – the first and second
vertebrae in the spinal column. The first vertebra (atlas) rotates around a
peg–like projection of the second vertebra (axis).
Move your neck to see the range of movements that are possible.
Which movements are the result of the pivot joint between the axis and the
atlas?
_________________________________________________________
_________________________________________________________
Check your answer.
Double hinge joint
A double hinge joint is like a hinge joint that also allows sideways
movement eg. spreading the fingers.
The knuckle joints in the hand are examples of double hinge joints.
This is where the bones of the palm join the bones of the fingers.
1
Move your fingers at the knuckle joints. Sketch a diagram of your hand
then draw arrows on the diagram showing the range of movements
possible. Use thick arrows to show the main directions and thinner
arrows showing the other directions of movement.
2
Your jaw is another example of a double hinge joint. Again, sketch
your face and use arrows to indicate the directions of movement in
your jaw.
Check your answers.
Part 4: Bone to bone
11
Did you know...?
The joint formed by the carpal bone and the metacarpal of the
thumb is not a ball and socket joint. This joint is an example of a
saddle joint. The bone extremities are shaped like a saddle in this
synovial joint as shown below.
The thumb joint is an example of a saddle joint
Locate this joint in your hand. What sorts of movements are possible?
_________________________________________________________
_________________________________________________________
Check your answers.
Turn to Exercise 4.2 at the back of this part to locate the different types of
joints and the range of movements they allow.
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Artificial joints
Silicone joints
Joints can be damaged through sports or accidents or degrade as a result
of arthritis. In many cases a diseased or damaged joint can be replaced
by an artificial joint.
Silicone is an organic compound which is non–reactive with body tissue.
This means that body tissue will not reject a silicone implant by swelling
and becoming inflamed and tender. Silicone is also unlikely to degrade
when surrounded by body tissue.
Rubber and silicone have several similarities however silicone possesses
several other important properties.
Use the code below to identify the properties of silicone.
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
1
flexible
_____________________________________________________
2
holds a particular shape
_____________________________________________________
3
light weight
_____________________________________________________
4
smooth
_____________________________________________________
Part 4: Bone to bone
13
5
acid resistant
______________________________________________________
6
impervious to water
______________________________________________________
7
cracks under moderate pressure
______________________________________________________
8
absorbs impacts
______________________________________________________
Check your answers.
It is these properties that make silicone a suitable substitute for small
artificial joints in the fingers and toes. The fingers and toes generally
bear little force (unless lifting weights). Therefore, it is unlikely silicone
joints in the fingers and toes will break or crack.
You may have heard of the bionic man. The term bionic refers to the
scientific study of living things as functional models for technical
development of therapeutic devices, which imitate the functions of
particular body parts. A bionic device is therefore an artificial body part
specifically designed to function in a similar way to natural body parts.
You have already studied pacemakers and artificial heart valves.
These are examples of bionics.
The two diagrams below demonstrate replacement silicone joints implanted
in a hand and foot. Colour in the replacement silicone joints.
knuckle joints
are replaced
by silicone
joints
Replacement silicone joints in knuckle
joints.
14
toe joints
are replaced
by silicone
joints
Replacement silicone joints in toe joints.
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You are required to investigate some of the properties of silicone.
You should have received a 20 cm silicone strip from your teacher.
You will plan and carry out tests on the strip of silicone, then relate these
findings to the silicone used in artificial joints. If you have not yet
received your silicone strip, contact your teacher now.
Turn to Exercise 4.3 at the back of this part to plan, carry out and report on
an investigation into the properties of silicone.
Add relevant information on implants to your database or the table in
Appendix 1 from Part 1. This information will be returned with the
exercises in Part 4.
Large artificial joints
Ball and socket joints are examples of large joints that can degrade with
arthritis. The cartilage covering the ends of bones becomes inflamed, as
the body’s own defenses attack the joint, destroying it as it would
harmful bacteria. Ultimately the joint becomes very painful to move.
Joints can also be damaged through impact sports over time and joint
bones can become weak with age or diseased.
Medical science has developed various artificial ball and socket joints,
which are designed to replace worn joints, giving people greater freedom
of movement and quality of life.
The diagram on the below shows a typical ball and socket hip joint.
The diagram on the next page shows the components of an artificial ball
and socket hip joint. The components of the natural joint and artificial
joint look similar.
femur
pelvis
Typical ball and socket hip joint.
Part 4: Bone to bone
15
acetabular
component
(lined with
UHMWPE)
femoral head
(covered in
UHMWPE)
femoral stem
(superalloy)
Artificial ball and socket hip joint.
The diagrams below show X–rays of artificial hip joints implanted
in 1985 and those used today.
Hip replacement 15 years ago
© Fran Philipson
Recent hip replacement
© Orana Radiology.
In 1985 metal rods were screwed to the outside of bone. Today an
artificial stem is placed inside the femur (thigh bone).
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You might be wondering what materials comprise an artificial hip.
The Artificial joints section of the Bionics audiotape answers this
question and many more.
Listen to the Artificial joints section of the Bionics audiotape/internet audio
file. Listen for important pieces of information and take notes in point form.
The object of this activity is for you to extract information on artificial
joints, not create a text copy of the audio.
You may need to stop the audio to jot down your points. The points should
consist of key words and should not take sentence form eg. ‘joints made of
superalloy metal,’ or ‘superalloy – cobalt/chromium and titanium’.
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
•
_____________________________________________________
Add relevant information on implants to your database or the table in
Appendix 1 from Part 1. This information will be returned with the
exercises in Part 4.
Part 4: Bone to bone
17
Life of replacement joints
The materials used in artificial joints are not able to regenerate and heal
as our joints do. Constant movement day after day, year after year takes
its toll on replacement joints. The Appendix discusses the problems
associated with artificial joints. Read the information in the Appendix
then answer the questions below.
1
Which part of an artificial joint wears first?
_____________________________________________________
2
Explain why this part of the replacement joint degrades.
_____________________________________________________
_____________________________________________________
_____________________________________________________
3
Explain the cause of artificial joints loosening over time.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
4
Explain one form of research aimed at improving the life of artificial
joints.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Check your answers.
Turn to Exercise 4.4 at the back of this part to address questions on artificial
joints.
Turn to Exercise 4.5 to complete the activity on biomedical implants from
Appendix 1, Part 1.
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Joint fixation
If you were to make a coffee table, you would probably use glue and
nails to hold the table together. How do you think artificial joints are
held in place in the body?
Years ago, a metal rod was attached outside the bone with screws as
shown on page 16.
Today’s hip replacements are attached to existing bone in one of two
ways: cemented and uncemented. Any materials used need to be
biocompatible, corrosion and wear resistant and able to support
weight–bearing loads.
About 80% of hip replacements last 20 years. X–rays of the hip region
showing the condition of the bone, age, weight, general health and
lifestyle are all used to decide whether a cemented or uncemented
implant is best for a patient. A person can walk without support almost
immediately after a cemented hip replacement. However, an uncemented
hip replacement may require a person to use crutches or a walker for
8–10 weeks. Uncemented implants are preferred for younger, active or
very heavy people.
For a cemented implant a fluid acrylic polymer that acts as a grout is
used. The cement is similar to that used by dentists to fix teeth.
This fluid penetrates into cracks and other spaces and solidifies, binding
bone and joint components together.
Uncemented implants use a porous, textured metal mesh into which
human bone grows. They are large and longer than cemented implants
and it takes much longer before the patient can walk unsupported after
the operation.
Try to find some people who have had implant operations who are willing
to share their experiences with you.
Part 4: Bone to bone
19
Use the above information to match the following questions with their
answers. Draw a line between the matching questions and answers.
What two methods are
employed to place implants in
the body?
The quality of the bone.
What determines if a doctor
cements or uncements an
implant into place?
A plastic compound.
How does acrylic (implant
cement) attach to bone?
It forms an interlocking
mechanical bond with the bone.
What is in implant cement?
Cementing and uncementing.
How do uncemented implants
form a bond with bone?
It forms an interlocking
mechanical bond with the bone.
Check your answers.
Turn to Exercise 4.6 at the back of this part to discuss cementing and
uncementing implants into place.
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Summary
Complete the following crossword using the clues on the following page.
1
2
1
4
3
5
9
4
6
7
8
10
12
11
13
15
16
14
17
18
19
21
20
22
23
24
25
Part 4: Bone to bone
21
Across
Down
1 a substance beginning with ‘t’ that
comprises artificial joints
1 tough, rope–like strands that connect
muscle to bone
3 the vertebrae joints are examples of
this type of synovial joint
2 the elbow is an example of this type of
joint
4 very strong, flexible substance present
in bones, ligaments and tendons
4 material covering the ends of bones
where bones meet at a joint
8 most of the joints in the body are these
type of joints
5 artificial joints may be cemented or
________________ into place
11 a structure that joins a bone to another
bone
6 silicone is an excellent substance in
joint replacement as it is inert, smooth
and ________________.
13 light flexible substance used as
replacement joints in fingers
14 joint type which allows the greatest
range of movement
17 artificial joints can contain this element
18 ultrahigh molecular weight polyethylene
23 the long section of a bone
25 ‘spongy’ bone
7 a substance often used to hold artificial
joints in place particularly in the thigh
bone
9 this joint is an example of a ball and
socket joint
10 knuckles are an example of this type of
joint
15 you tested silicone with vinegar to find
silicone is ______ ______________.
16 an example of a double hinge joint
19 a general term for the metals present in
artificial joints.
20 this metal can be part of a superalloy
21 the neck is and example of this type of
joint
22 the ends of bones
24 silicone joints can replace ____ joints
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Appendix
Studies have shown that superalloy metals show very little or no wear
over time, even after 15 years. The metal is clearly strong enough to last
for many years however, the joint itself had a limited life for
several reasons.
The constant rubbing action between the superalloy metal and the ultra
high molecular weight polyethylene (UHMWPE) causes the UHMWPE
to fatigue, causing greater resistance in the joint. In almost every case,
the UHMWPE degrades long before the superalloy metal.
The rubbing action also causes microscopic particles of the UHMWPE
and metal to be released into surrounding body tissue. The joint itself
still functions as normal, however the particles accumulating in
surrounding tissue are small enough for the body to consider them
harmful microbes. The body puts its defenses into motion, causing the
area to become inflamed. The cells around the area become overworked
in a fruitless attempt to destroy these particles. This then causes the bone
around the joint to degrade. The joint then becomes loose and painful.
This can take 15 to 25 years, however, the joint must be replaced.
Recent studies are blaming sterilisation procedures for this degradation.
Superalloy and UHMWPE joints are bombarded with gamma radiation in
the sterilising process. This aims to minimise infection in the joint once
implanted, however it is thought the radiation causes the polyethylene to
oxidise and begin to degrade, losing some mechanical properties.
Research is underway into alternative sterilisation methods.
Other research involves studies into the structure of synovial joint fluid,
enhancing the durability of the superalloy/UHMWPE interface and
causing the debris to break off in larger pieces.
Synovial fluid research aims to mimic the structure and lubricating
properties of synovial fluid for use in artificial joints. Recent research
suggests that bombarding the surface of superalloys with ions hardens the
outer surface, protecting it against destructive friction with UHMWPE.
This significantly reduces the amount of debris released in the joint over
time. Other research suggests that if the debris caused by joint friction
broke away in slightly larger chunks, the bodies defences would not
recognise the debris as harmful and would not attack it.
Part 4: Bone to bone
23
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Suggested answers
Joint structures
1
A rubbery substance covering ends of bones.
cartilage
2
‘Rubber bands’ that hold bones together.
ligament
3
Very strong flexible substance.
collagen
4
Connects muscle to bone.
tendon
5
Protects and supports bones against impacts.
cartilage
6
Lining on the inner surface of a joint capsule.
synovial membrane
7
Slippery fluid lubricating a joint.
synovial fluid
8
Prevents dislocation of bones.
ligament
Joint movement
1
The fibrous capsule encloses the joint.
2
The synovial membrane lines the joint capsule. It secretes synovial
fluid into the cavity.
3
Synovial fluid fills the joint cavity. It lubricates the joint and
provides nutrients.
4
Articular cartilage covers the end of the bones in a joint. It is
smooth, shiny and white. Articular cartilage reduces the friction
between the bones in a joint.
Factors affecting joint movement
1
The following determine the range of movement in a joint: the shape
of bone in the joint; the flexibility or elasticity of ligaments and
tendons; the strength and length of muscles around a joint; and the
presence of synovial fluid.
2
Sports that require sharp turns on the feet and shoulder impacts tend
to incur the most knee and shoulder injuries eg. basketball.
Part 4: Bone to bone
25
Ball and socket joint
Movement
Shoulder
Hip
lift limb forward
lift limb backwards
lift limb to the side
lift to the opposite side
rotate the limb in a circular motion
Hinge joint
You should only be capable of moving your forearm up and down from
the elbow and not side to side. This is because the joint is a hinge joint,
only allowing movement in one plane.
Sliding joint
You can bend further forwards than backwards because the extensions at
the back of the vertebrae inhibit the backwards–bending motion.
Pivot joint
The atlas pivot joint allows the head to look from side to side.
(Movement between the vertebrae also allows you to tilt your head
forward and back and from side to side).
Double hinge joint
The movement recorded for double hinge joints should have been side to
side, back to front and small rolling movements. (Your diagrams would
have been diagrams with arrows)
Did you know…? (saddle joint)
Side to side, rolling and a back to front sliding movements are possible
with the saddle joint.
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Silicone joints
1
flexible
2
holds a particular shape
3
light weight
4
smooth
5
acid resistant
6
impervious to water
7
cracks under moderate pressure
8
absorbs impacts.
Life of replacement joints
1
UHMWPE wears before the superalloy.
2
The UHMWPE sustains half the upper bodyweight and is subject to
the constant friction of metal moving against its surface. This causes
the UHMWPE to degrade over time.
3
Constant grinding action between the UHMWPE and superalloy
surface causes microscopic fragments to be released into the
surrounding tissue. The body attacks this debris as it would attack
bacteria. The area becomes inflamed and bone tissue becomes
exhausted from the fruitless fight against the debris, causing the
bone to degrade, loosening the joint.
4
Research is underway into alternative sterilisation methods; the
structure of synovial joint fluid; enhancing the durability of the
superalloy/UHMWPE interface; and causing the debris to break off
in larger pieces.
Part 4: Bone to bone
27
Joint fixation
What two methods are employed to
place implants in the body?
Cementing and uncementing.
What determines if a doctor cements
or uncements an implant into place?
The quality of the bone.
How does acrylic (implant cement)
attach to bone?
It forms an interlocking mechanical
bond with the bone.
What is in implant cement?
A plastic compound.
How do uncemented implants form a
bond with bone?
The implant metal has a porous,
textured, mesh–like surface into
which the bone grows.
Summary
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Exercises - Part 4
Exercises 4.1 to 4.6
Name: _________________________________
Exercise 4.1
Aim
To investigate the relationship between cartilage, muscle and tendon in
an animal limb.
Apparatus
Collect the following:
•
fresh chicken wing
•
small pair of scissors
•
small sharp knife
•
tweezers
•
board or dish to hold the specimen being dissected.
Method
Read through steps 1 – 8 before commencing wing dissection.
1
Examine the chicken wing. Move the joints and note the direction
the bone moves. (Be careful not to damage the joint.) Identify the
types of synovial joints in the wing.
2
Use the scissors and sharp knife to peel away the skin of the wing,
leaving the structures visible underneath. Be careful to avoid
damaging muscles, tendons, ligaments and cartilage.
3
Locate a large muscle and trace it from one end to the other, locating
the tendons at each end. (Refer to page 4 to recall the definition of a
tendon.)
4
Pull on the tendons and note the movement.
Part 4: Bone to bone
29
5
Using your dissecting instruments, separate the muscle from the
other tissue and trace the tendons to their origins.
6
Clear away the tissue from the central joint to locate the ligaments.
(Refer to page 4 to recall the definition of a ligament.)
7
Locate the cartilage in the joint. (Refer to page 4 to recall the
definition of cartilage)
8
Make one or two clear and accurate diagrams of the muscle(s),
tendons, ligaments, cartilage and bone, labelling these structures.
Results
Make clear and accurate diagram(s) of the muscles, tendons, ligaments,
cartilage and bone in the chicken wing. Identify these structures using
two diagrams. (Use pencil.)
Conclusion
Explain the relationship between ligament, cartilage, muscle, tendon and
bone in a chicken wing in one paragraph.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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Exercise 4.2
Choose four joint types from the following list:
•
ball and socket joint
•
hinge joint
•
pivot joint
•
sliding joint
•
double hinge joint
•
saddle joint.
a)
Indicate one site each for the four joint types, showing locations on
the body diagrams below.
b) Indicate all the range of movements possible for each of the four
joints. You may use arrows and/or sketch in limbs showing the
range of motion possible on the front and side diagrams below.
(Use pencil.)
Part 4: Bone to bone
31
Exercise 4.3
You are required to investigate some of the properties of silicone:
Plan, choose equipment or resources for and perform a first–hand
investigation to demonstrate the properties of silicone such as acid
resistance, flexibility and imperviousness to water that make it
suitable for use in bionics.
Extract from Senior Science Stage 6 Syllabus © Board of Studies NSW, 1999.
You should recall the following properties of silicone:
•
flexible
•
holds a particular shape
•
light weight
•
smooth
•
acid resistant
•
impervious to water
•
cracks under moderate pressure
•
absorbs impacts.
Some hints for designing your investigation are:
•
vinegar is an acid; evidence of a reaction with acid is: bubbling;
dissolving of the substance
•
a substance may be weighed, submerged in water and reweighed to
determine if it has absorbed water
•
a substance which absorbs impacts will bounce back to its original
shape after a force is applied
•
the silicone may be cut into pieces to be tested.
Are you ready to plan your investigation?
Aim
What are you trying to find out? (refer to the syllabus extract above)
_________________________________________________________
_________________________________________________________
Apparatus
What will you need to carry out your investigation? Explain why you
will require each piece of equipment listed on the right.
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Apparatus
Justification
_____________________
_______________________
_____________________
_______________________
_____________________
_______________________
_____________________
_______________________
_____________________
_______________________
Method
How will you carry out your investigation? Remember that you must test
acid resistance, flexibility and imperviousness to water. However, you
may choose to test all the properties of silicone.
Present your method in a sequential format and justify your choice of
procedure on the right for each step. Space for your method continues on
the next page.
Method
Justification
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
Part 4: Bone to bone
33
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
________________________________
_______________________
Results
How will you record your results for each type of test? How will you
highlight your results? Will you include drawings or photographs? The
lines on the following page before the conclusion are for you to justify
your choice of results presentation.
34
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Justify your presentation of the results.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Conclusion
Describe properties of silicone based on your results.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Discussion
Explain how each of the properties of silicone makes it suitable for use in
bionics. (Imagine the conditions that would exist inside the body, such
as a watery environment, to help you explain your answer.)
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 4: Bone to bone
35
Exercise 4.4
a)
Identify two types of superalloys used in artificial joints.
______________________________________________________
b) Explain four properties of superalloys that make them suitable as
bone components of artificial joints.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
c)
What does UHMWPE stand for?
______________________________________________________
d) Label parts of the artificial hip joint below as superalloy and
UHMWPE.
e)
What does UHMWPE mimic in normal synovial joints and why is it
necessary?
______________________________________________________
______________________________________________________
______________________________________________________
f)
Compare the strength of UHMWPE and ‘superalloy’ metal.
______________________________________________________
______________________________________________________
______________________________________________________
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g) What three properties make UHMWPE useful in artificial joints?
Explain your answer.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
h) Colour in the area(s) of the artificial hip joint that degrades most
after years of use.
Exercise 4.5
By now you should have compiled information about implants – their
type, materials and parts of the body. This should be in the form of a
database. If this was not possible, you would have compiled your data as
a table.
You can present this information to your teacher as a database (on disk,
CD or as a print out) or as a completed table (from Appendix 1) in Part 1.
Attach this information to this page.
Part 4: Bone to bone
37
Exercise 4.6
‘An elderly person with weak bones and poor bone regrowth is likely to
have an artificial joint cemented into place rather than uncemented.’
While describing how cemented implants attach to bone and how
uncemented implants bond with bone, explain why the above statement
would be true or false..
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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Senior Science
HSC Course
Stage 6
Medical technology – bionics
Part 5: Breathing easy
0
20
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Senior Science Stage 6 HSC Course
Lifestyle chemistry
Medical technology – bionics
•
Spare parts
•
Fixing a broken heart
•
Heart to heart
•
Bone to bone
•
Breathing easy
•
Peak–a–boo
Information systems
Option
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Contents
Introduction ............................................................................... 2
Technology and the body .......................................................... 4
The respiratory system.............................................................. 5
Function of the respiratory system ......................................................5
Structure of the respiratory system .....................................................6
How do I breathe?..............................................................................10
Exhaling carbon dioxide.....................................................................13
Cardiopulmonary resuscitation ..........................................................13
Life support systems ............................................................... 15
Summary................................................................................. 17
Appendix 1 .............................................................................. 19
Appendix 2 .............................................................................. 21
Suggested answers................................................................. 23
Exercises – Part 5 ................................................................... 25
Part 5: Breathing easy
1
Introduction
You will gain an understanding of technologies’ contribution to our
understanding of how the body works; the function of the respiratory
system and the technologies used to sustain life during Part 5. You will
be involved in researching information, listening to an audiotape/internet
audio files, interacting with diagrams and writing in circles.
In this part, you will be given opportunities to learn to:
•
describe the structures of the respiratory system and identify their
function including
–
trachea
–
bronchi
–
alveoli
–
capillary network around the alveoli
•
explain why cardiopulmonary resuscitation techniques can maintain
life when the heart has ceased beating
•
identify that artificial lungs remove carbon dioxide from the blood
and replace it with oxygen
•
discuss the type of operations that would require the use of an
artificial lung
•
identify devices that constitute life support systems in any major
hospital.
In this part, you will be given opportunities to:
2
•
perform an investigation to model the action of the diaphragm in
inhalation and exhalation
•
perform a first–hand investigation to identify carbon dioxide in
inhaled air and in exhaled air and determine which has the greater
concentration
•
gather, process and present information from secondary sources to
identify monitoring and other devices that constitute life support
systems and use available evidence to explain their roles in
maintaining life.
Medical technology – bionics
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•
gather, process and analyse information and use available evidence
to discuss how technological developments have impacted on the
understanding of how the body works.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
November 2002. The most up-to-date version can be found at
http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
Part 5: Breathing easy
3
Technology and the body
These days, doctors seem to know all there is to know about the body
and how it works. Have you ever stopped to think ‘how do they know’?
Do you think we would know so much without technology?
Technological advances have allowed a detailed study of the human
body. Doctors can use technology to assist in the diagnosis of disease
and injury in the following ways.
•
Identification of broken bones, locate tumors in the brain and map
our genes.
•
Women can have ultrasounds to check development of a baby;
mammograms to screen for breast cancer; and pap smears to screen
for cervical cancer.
•
X–rays detect bone abnormalities; CT (computerised tomography)
scans can map different parts of the body also detecting
abnormalities; and an ECG (electrocardiograph) can detect
abnormalities in the heart.
•
Keyhole surgery uses a tiny camera on the end of a probe to
identify abnormalities anywhere in the body.
•
Blood can be tested for anything from sugar levels and viruses to
iron levels and antibodies, while DNA tests can determine a
person’s parentage.
These are only a few technological advances, helping doctors to
understand how the body works.
Turn to Exercise 5.1 to research two different technological developments
and their impact on the understanding of how the body works.
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The respiratory system
Your lungs are part of your respiratory system. You may remember
how they work to exchange carbon dioxide and oxygen with the air.
The following section should help you recall the role of the respiratory
system in maintaining you as a functioning organism.
Function of the respiratory system
The lungs and air passages transport air from the external environment
to the blood vessels where oxygen can be absorbed and carbon
dioxide removed.
All cells carry out respiration. Glucose is oxidised to produce carbon
dioxide, water and energy. This process, called cellular respiration,
requires oxygen. Cells obtain energy for body processes
through respiration.
The following equation summarises and simplifies respiration as it
occurs in the cells in your body. You should remember this equation
from the Plants module in the preliminary course. The function of
respiration is to release energy for the body to use.
oxygen + glucose
carbon dioxide + water + energy
Oxygen needs to be supplied to cells for respiration (energy production)
to occur.
1
How does oxygen enter the body?
_____________________________________________________
Water and carbon dioxide (waste products from respiration) must be
removed from cells in the body.
Part 5: Breathing easy
5
2
Where is water removed from the body?
______________________________________________________
3
Where is carbon dioxide removed from the body?
______________________________________________________
Check your answers.
The respiratory system exchanges oxygen and carbon dioxide with the
environment. Respiratory organs transport air to the blood vessels for the
exchange of gases to take place. Air is also returned to the environment
by the respiratory system.
The respiratory system and the circulatory system work together to
supply all cells with oxygen and to remove carbon dioxide.
Structure of the respiratory system
The following diagram lists the main parts of the respiratory
system.
nose
nasal passage
trachea wall
(magnified)
epiglottis
cilia
to the stomach
trachea
bronchus
bronchiole
alveoli
rib
right lung
showing
lobes
diaphragm
left lung
dissected to show
internal structure
air
capillaries
cluster of
alveoli
alveolus
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Air enters the lungs when we breathe in (inhale) through the nose
and mouth. Trace the passage of air into the lungs using the
previous diagram.
Colour the organs the air passes through in order from the mouth and nose
until it reaches the alveoli.
a)
Colour the trachea red.
b) Colour the bronchi in orange.
The bronchi divide into the bronchioles. Bronchioles then divide into
alveoli which are small round pockets supplied with a great deal of blood.
At what site do you think most gas is exchanged?
_________________________________________________________
Check your answers.
Alveoli and gas exchange
Oxygen and carbon dioxide are exchanged between the air and the blood.
This occurs across the walls of the alveoli. This is the site of gas
exchange. Alveoli are covered with very narrow blood vessels called
capillaries. This is shown in the diagram below.
Part 5: Breathing easy
7
1
The lines running over the grape–like structures on the previous page
are capillaries.
Label capillaries on the diagram.
2
Draw the capillaries on the alveoli without capillaries. Remember this
is the site of gas exchange so there are lots of them!
3
Blood comes to the alveoli through the pulmonary artery from the heart.
This blood is low in oxygen and high in carbon dioxide when it arrives
in the lungs – the blood is actually bluish in colour when depleted of
oxygen.
Colour the arteries blue.
4
Gas exchange occurs between the capillaries and the alveoli.
Carbon dioxide moves from the blood in the capillaries into the
alveoli. Oxygen moves via diffusion from the air in the alveoli into
the blood through the capillary wall.
Shade in the area where this occurs on one of the alveoli
cross–sections.
5
Blood leaves the lungs through the pulmonary vein, and travels back
towards the heart. It is high in oxygen and low in carbon dioxide
when it leaves the lungs. The blood is red in colour.
Colour the veins red.
Air leaves the lungs through the bronchioles then the bronchi, then the
trachea when we breathe out (exhale). This air is higher in carbon dioxide
and lower in oxygen.
You have already coloured in the bronchi and trachea in a previous diagram.
What colour are these structures?
_________________________________________________________
Check your answer.
Gas exchange – up close
The alveoli provide a large surface area for a greater quantity of gas
exchange. The moist, thin walls of the alveoli allows for rapid diffusion
of oxygen into the blood and carbon dioxide out of the blood.
Without moisture, the gases would not be able to dissolve and move
across the thin membranes.
The diagram on the following page shows the exchange of gases between
the alveoli and the capillaries on a microscopic scale.
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Label the following structures on the diagram below. The labels appear in
italics.
1
The dark arrow at the top of the diagram indicates blood low in oxygen
and high in carbon dioxide from the body.
2
The structure surrounding the alveoli cavity is the blood capillary.
3
The wall surrounding the alveoli cavity is the wall of alveolus.
4
The double headed arrow indicates inhaled and exhaled air.
5
Each circle inside the blood capillary represent a blood cell.
6
The arrow from the blood capillary into the alveoli cavity indicates
movement of carbon dioxide.
7
The arrow from the alveoli cavity to the blood capillary indicates
oxygen movement.
8
The dark arrow at the bottom of the diagram indicates blood flow to
the body, high in oxygen and low in carbon dioxide.
Exchange of gases at the alveoli in the lungs.
Check your answers.
Part 5: Breathing easy
9
How do I breathe?
Have you ever wondered how your body works to exchange gases with
the air? Do you have any ideas? See if your ideas are correct by reading
the following.
There are two ways gases move. These are by diffusion and across
pressure gradients. Your lungs utilise differences in pressure to draw
air into your lungs and expel air from the lungs. The structures most
responsible for causing this difference in pressure are the
diaphragm (die–ah–fram).
Locate the diaphragm on the diagram below.
Gases always move from areas of high pressure to areas of low pressure.
For you to inhale, your lungs must have lower pressure than the pressure
outside your body. The air will move from high pressure outside your
body to the area of low pressure inside your lungs. For you to exhale,
your lungs must have higher pressure than the pressure outside your
body for the air to move from high to low pressure, out of the body.
Did you find that explanation confusing? The following activity
may help.
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You should have seen weather maps that have areas of high (H) and areas of
low (L) pressure. High and low pressures are indicated on the lungs below
as H and L inside circles.
1
Draw arrows pointing from the H to the L through the trachea on the
lungs below, as this shows movement of air from high pressure to low
pressure.
2
Circle the correct word in the sentence below each diagram.
L
mouth and nose
cavity
L
trachea
L
L
H
H
lung
L
L
This diagram shows a person inhaling/exhaling.
mouth and nose
cavity
H
H
trachea
H
H
L
L
lung
H
H
The diagram shows a person inhaling/exhaling.
Part 5: Breathing easy
11
You may be wondering how the lungs can alter their pressure from high to
low. The diaphragm is primarily responsible for this. So how does it work?
The process is really quite simple. Refer to the diagrams below.
high
pressure
low
pressure
low
pressure
•
As the diaphragm lowers
through muscle
contraction the lungs
expand.
•
This creates low pressure
inside the lungs.
•
The air then moves from
high pressure outside the
lungs to low pressure
inside the lungs.
•
As the diaphragm rises
through muscle relaxation
the air inside the lungs
experiences high pressure.
•
The air then moves out of
the lungs from high
pressure to low pressure.
lung
diaphragm
lowers
low
pressure
high
pressure
high
pressure
lung
diaphragm
rises
3
Explain how you inhale.
______________________________________________________
______________________________________________________
4
Explain how you exhale.
______________________________________________________
______________________________________________________
Check your answers.
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Turn to Exercise 5.2 at the back of this part to investigate the action of the
diaphragm in inhalation and exhalation.
Exhaling carbon dioxide
How do you know the air you exhale has a higher concentration of
carbon dioxide than the air you inhale?
We know that limewater (calcium hydroxide and water) turns from
clear to a milky colour when in the presence of carbon dioxide.
The calcium hydroxide reacts chemically with the carbon dioxide to form
calcium carbonate.
In this activity you will need a small amount of lime (a source of calcium
hydroxide). You may be able to obtain this from your teacher, a
bricklayer or builder or a hardware store.
Turn to Exercise 5.3 at the back of this part to investigate carbon dioxide in
exhaled air.
Cardiopulmonary resuscitation
Do you remember how the heart works from Part 1? The heart keeps
blood pumping to the lungs and body. See if you can fill in the missing
words in the sentences below.
1
Blood, which is low in ________________ and rich in ____________
________________ is pumped from the _____________ to the lungs.
2
Here, the blood exchanges carbon dioxide for ______________ in the
_______________, then travels back to the heart where it is pumped
around the _________________.
Check your answers before moving on.
What if the heart stops? Blood can’t be pumped to the lungs to take
oxygen to the cells. The body would starve for oxygen and cells would
begin to die.
You are capable of keeping a person alive when their heart has stopped.
It is likely you already know how to apply cardiopulmonary
Part 5: Breathing easy
13
resuscitation (CPR). CPR consists of both expired air resuscitation
(EAR), filling the lungs with air, and external cardiac compression
(ECC), keeping the heart pumping blood. The diagram on the following
page shows two students practicing CPR (EAR and ECC) on a dummy.
Never practice CPR on anybody whose heart is already beating.
Students practising CPR on a dummy model of a human being (student on the
left ECC, student on the right EAR).
External cardiac compression (ECC) is applied to the sternum
(breastbone) of a person who is unconscious and without a pulse.
The action of pressing on the sternum, directly above the heart (at one
second intervals) keeps blood pumping around the body.
Expired air resuscitation (EAR) applied in conjunction with CPR
provides the blood with oxygen. This is achieved by exhaling air into the
victim’s lungs.
The application of ECC and EAR can mean the difference between life
and death. If body cells can continue to exchange carbon dioxide with
oxygen in the blood, cells can be kept alive until the body can resume
normal functions.
3
Answer the following question as you would if you were sitting your
final HSC exam. Your answer should be explanatory and concise.
Explain why cardiopulmonary resuscitation techniques can maintain
life when the heart has ceased beating.
______________________________________________________
______________________________________________________
Check your answers.
There are other ways a person may be kept alive when the heart has
stopped beating. These are called life support systems.
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Life support systems
Medical engineers have developed several devices that will sustain
human life. This section looks in detail at the various life support
systems in use in major hospitals.
University students often sit in lecture theatres, jotting down relevant
notes from information given orally by a lecturer. For this activity,
imagine you are a university student. Your lecturer gives you a hand
out, outlining what the lecture will be about. The points on the handout
include:
•
life support devices in major hospitals
•
the function of artificial lungs
•
the types of operations requiring use of an artificial lung
•
life support monitoring devices.
This list gives you some guidance on what you should take notes on
during the lecture.
Listen to the Life support systems section of the Bionics audiotape/internet
audio files. Imagining you are a university student, take your own notes
based on the information in the lecture. Room for your notes is provided
below and on the following page.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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15
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Turn to Exercise 5.4 at the back of this part to explain the roles of specific
devices in maintaining life.
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Summary
Have fun filling in the blanks below.
Part 5: Breathing easy
17
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Appendix 1
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Appendix 2
Artificial respirator.
Heart monitor and defibrillator
Part 5: Breathing easy
21
external fitting
implant several feet long
a thousand
hollow fibre
membranes
carbon dioxide
oxygen
helium
}
several millimetres
to fit into a vein
expanding helium
balloon
Artificial lung.
A heart lung machine. Accessed from
<www.njbusinessguide.con//riz/heart–_lung_machine.htm> Downloaded 28
November 2000.
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Suggested answers
The respiratory system
1
Oxygen enters the body through the lungs.
2
Water is filtered by the kidneys and exits the body through the
urinary system and perspiration. Some water escapes in exhaled air.
3
Carbon dioxide leaves the body through the lungs.
Structure of the respiratory system
The site of most gas exchange is the alveoli.
Alveoli and gas exchange
The bronchi are coloured orange; the trachea, red.
Gas exchange – up close
blood from body
(low in oxygen, high in carbon dioxide)
blood capillary
wall of alveolus
air inhaled
air exhaled
carbon dioxide
oxygen
blood cell
Part 5: Breathing easy
blood to rest of body
(high in oxygen,
low in carbon dioxide)
23
How do I breathe?
1
L
mouth and nose
cavity
L
trachea
L
L
H
H
lung
L
L
The diagram shows a person exhaling.
mouth and nose
cavity
2
H
H
trachea
H
H
L
L
lung
H
H
The diagram shows a person inhaling.
3
The diaphragm lowers causing low pressure inside the lungs.
The higher pressure outside the body causes air to move from high to
low pressure, into the lungs, causing inhalation.
4
As the diaphragm rises, the lungs experience a higher pressure than
the air outside the body. The air moves from high pressure to low
pressure, causing air to move out of the lungs as exhalation.
Cardiopulmonary resuscitation
24
1
Blood, which is low in oxygen and rich in carbon dioxide is pumped
from the heart to the lungs.
2
Here the blood exchanges carbon dioxide for oxygen in the alveoli,
then travels back to the heart where it is pumped around the body.
3
CPR techniques use chest compressions above the heart to keep
blood pumping around the body, delivering life–giving oxygen to
body cells. This can keep a person alive until the body can resume
its normal functioning. Other answers are acceptable.
Medical technology – bionics
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Exercises - Part 5
Exercises 5.1 to 5.4
Name: _________________________________
Exercise 5.1
Many technological developments have allowed the body to be studied in
great detail. Choose two such technological developments (some ideas
are available on page 4).
For each of the two technological developments:
•
state the technological development
•
briefly explain what the technology does or what it is used for
•
explain how knowledge of the body and how the body works has
improved as a result of this technology
•
clearly identify your source of information by stating: the author;
date of publication; title of the book or article; publisher; the place of
publication or the website address. (You may also attach copies of
the information you used.)
Tick the sources of information you are able to access below.
books and encyclopedias from your school library or local library
Internet
local hospital staff
local surgery
telephone contact with major hospitals
other
A table is available for your answer on the following page.
Part 5: Breathing easy
25
Technological development
Technological development
Use of technology
Use of technology
How knowledge of the body has improved
with this technology
How knowledge of the body has improved
with this technology
Source of information
Source of information
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Exercise 5.2
Turn to the diagrams in Appendix 1 which demonstrate an experiment.
These diagrams show the action of the diaphragm in expanding the lungs.
Use the diagrams in Appendix 1 to complete the following.
1
Write an aim for this experiment.
_____________________________________________________
_____________________________________________________
2
Record all the apparatus present in the diagrams.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
3
Once the apparatus is assembled, explain what is manipulated to
cause the apparatus to work.
_____________________________________________________
_____________________________________________________
_____________________________________________________
You may refer to page 11 and 12 which discusses high and low pressure
associated with the movement of air in the lungs to help you complete
the following questions.
4
Cut out the diagram from Appendix 1 showing the expanded
balloons and glue it below on the left. With reference to areas of
high and low pressure inside the balloon and outside the jar, explain
why the balloons in the bell jar have expanded.
_____________________
_____________________
_____________________
_____________________
_____________________
_____________________
_____________________
_____________________
Part 5: Breathing easy
27
5
Cut out and glue in the diagram from Appendix 1 with the deflated
balloons. With reference to areas of high and low pressure, explain
why the balloons are deflated.
_____________________
_____________________
_____________________
_____________________
_____________________
_____________________
_____________________
_____________________
6
You know that the diaphragm is important for the action of
breathing. Explain how the pictures demonstrate the diaphragm’s
action of drawing air into the lungs and expelling air from the lungs.
Use the following terms and highlight each of them in your
explanation:
•
high pressure
•
low pressure
•
expand
•
deflate
•
diaphragm
•
down
•
up.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
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Exercise 5.3
The materials you will need for this activity are italicised in the sentences
below. Search through the text for these items and collect them before
beginning your experiment. Make sure you read and heed the safety
warnings before you use lime.
1
Limewater is made by adding a small amount of lime (lime can be
obtained from a bricklayer, builder or hardware store) in a medium jar
with 2 cups of water.
Shake well.
Keep the lime away from your eyes and skin. Lime or limewater in the eyes
must be immediately washed away with lots of water.
Allow the jar to stand until the water appears clear and the excess
calcium hydroxide has settled to the bottom. Leave overnight with
the jar covered to minimise exposure to the air.
2
Gently pour the same amount of the clear liquid into two small clean
glasses, being careful not to disturb the calcium hydroxide on the
bottom of the jar.
3
For one of the samples of clear liquid, whisk it for one minute with a
small whisk or with a fork.
4
Was there any change in the colour of the liquid? Record your
observations below.
_____________________________________________________
5
Use the information on page 13 to explain what your observation
indicates.
_____________________________________________________
_____________________________________________________
_____________________________________________________
6
Use a straw to blow air from your lungs into the second sample of clear
liquid for one minute.
Ensure that you blow through the straw; do not draw liquid up the straw.
7
What observation did you make?
_____________________________________________________
8
Use the information on page 13 to explain what your observation
indicates.
_____________________________________________________
_____________________________________________________
Part 5: Breathing easy
29
______________________________________________________
9
Which sample contains the greater concentration of carbon dioxide?
Explain why.
______________________________________________________
______________________________________________________
Exercise 5.4
Explain the role of two of the following devices in maintaining human
life.
•
artificial respirator
•
artificial lung
•
heart lung machine
•
monitoring devices
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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Senior Science
HSC Course
Stage 6
Medical technology – bionics
Part 6: Peek-a-boo
0
20
In
r
e
to b T S
c
O EN
g
in D M
t
a
r EN
o
p
r
co A M
2
Senior Science Stage 6 HSC Course
Lifestyle chemistry
Medical technology – bionics
•
Spare parts
•
Fixing a broken heart
•
Heart to heart
•
Bone to bone
•
Breathing easy
•
Peek–a–boo
Information systems
Option
Gill Sans Bold
Contents
Introduction ............................................................................... 2
Non-invasive medical techniques .............................................. 3
X-rays....................................................................................................4
Magnetic resonance imaging (MRI) ....................................................4
Ultrasound ............................................................................................5
Thermography ......................................................................................7
Minimally invasive medical techniques...................................... 9
Appendix 1 .............................................................................. 11
Appendix 2 .............................................................................. 13
Suggested answers................................................................. 15
Exercises – Part 6 ................................................................... 17
Part 6: Peek-a-boo
1
Introduction
Part 6 gives you opportunities to learn the different non–invasive and
minimally invasive medical techniques. You will also revise Parts 1–6
while completing an open book practice test.
In this part you will be given opportunities to learn to:
•
discuss the terms non–invasive and minimally invasive in relation to
medical techniques
•
identify non–invasive diagnostic techniques including X–rays,
ultrasound, thermography and magnetic resonance imaging (MRI)
and discuss their importance in diagnostic medicine
•
describe the advantages of using minimally invasive surgery
techniques such as keyhole surgery.
In this part you will be given opportunities to:
•
identify data sources, gather, process, analyse and present
information to discuss the advantages and disadvantages of
non–invasive and minimally invasive medical techniques.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
November 2002. The most up-to-date version can be found at
http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
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Non-invasive medical techniques
You have worked well through Parts 1 to 5 to get to this point. You have
read through several long appendices to gather information.
The majority of information and instructions for Part 6 is presented on
side B of the Bionics audiotape to allow you to gather information from
an auditory, rather than visual source. You can also access the same
auditory information through the www.lmpc.edu.au/science web site.
Listen to the information and follow the instructions on the Non–invasive
medical techniques section of the Bionics audiotape/internet audio files.
The audio will instruct you as to how to complete the activities throughout
this part.
You will be introduced to various non–invasive medical techniques such as
X–rays, magnetic resonance imaging, ultrasounds and thermography.
1
Define non–invasive medical techniques
_____________________________________________________
_____________________________________________________
2
X–ray
maps slices of the body to detect
bone and tissue irregularities
ultrasound
detects irregularities in body
temperature
MRI (magnetic resonance
imaging)
detects irregularities in bones and
soft tissues
thermography
detects irregularities in body soft
tissue
Check your answers.
Part 6: Peek-a-boo
3
X–rays
Spine X–ray.
X–ray of large intestine.
X–ray summary
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Magnetic resonance imaging (MRI)
Magnetic resonance image of the
spinal column and ribs
Magnetic resonance images of
the spine
Courtesy of Fran Philipson.
MRI summary
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_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Ultrasound
image of
inside the
knee
transducer
computer
knee
The process involved in gaining an ultrasound image.
Check your answers.
Part 6: Peek-a-boo
5
area of ultrasound scan
amniotic sac
amniotic fluid
12 week foetus
Examples of ultrasound images.
Ultrasound summary
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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Thermography
Part 6: Peek-a-boo
7
right leg
left leg
5
4
4
3
2
2
1
3
4
4
2
3
2
3
3
1
4
3
3
A thermographic image of legs with injuries.
Thermography summary
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Turn to Exercise 6.1 at the back of this part to complete an activity on
non–invasive medical techniques.
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Minimally invasive medical techniques
Listen to the Minimally invasive medical techniques section of the Bionics
audio to write your own points around the key hole diagram below.
Part 6: Peek-a-boo
9
knee cap
(patella)
1
5
4
2
3
Key hole surgery in knee joint.
Check your answers.
You may be able to access the www.lmpc.edu.au/science web site to
view a short video of an arthroscopy. This video shows an operation on
cartilage inside a knee using keyhole surgery.
Turn to Exercise 6.2 at the back of this part to demonstrate your
understanding of minimally invasive medical techniques.
Turn to Exercise 6.3 at the back of this part to complete a practice test on the
Medical technology – bionics module.
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Appendix 1
Fractured bone.
Part 6: Peek-a-boo
11
12
Medical technology – bionics
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Appendix 2
3
1
2
4
6
5
7
Part 6: Peek-a-boo
8
9
13
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Suggested answers
Non–invasive medical techniques
1
Non–invasive medical techniques are those that can give information
about the body without physically invading or entering the body.
2
X–ray detects irregularities in bones.
Ultrasound detects irregularities in body tissue.
MRI (magnetic resonance imaging) maps slices of the body to detect
bone and tissue irregularities.
Thermography detects irregularities in body temperature.
Ultrasound
transducer
transmits sound
waves to the
body
collected sound
waves are
converted to a
computer image
reflected sound
waves are
collected by
the transducer
knee
Part 6: Peek-a-boo
image of
inside the
knee
computer
structures inside the
knee reflect sound
waves
15
Minimally invasive medical techniques
knee cap
(patella)
1
5
arthrscopic
instrument
arthroscope
4
2
3
ligament
16
cartilage
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Exercises - Part 6
Exercises 6.1 to 6.3
Name: _________________________________
Exercise 6.1
Write the type of non–invasive medical technique above each of the
images and record the advantages and disadvantages for each.
Advantages
Part 6: Peek-a-boo
Disadvantages
Image
17
Exercise 6.2
a)
Define minimally invasive surgery.
______________________________________________________
______________________________________________________
b) Explain the process of keyhole surgery as opposed to open surgery.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
c)
Explain the advantages of minimally invasive surgery.
______________________________________________________
______________________________________________________
______________________________________________________
d) Explain the major disadvantage of keyhole surgery.
______________________________________________________
______________________________________________________
______________________________________________________
e)
Provide three examples of medical procedures that can be achieved
through minimally invasive keyhole surgery.
______________________________________________________
______________________________________________________
______________________________________________________
f)
Give three examples of interesting things you learned from the
Minimally invasive medical techniques section of the Bionics
audiotape.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
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Exercise 6.3
This exercise is an open book practice test for Medical technology –
bionics. Use Parts 1 – 6 to complete this exercise.
Part A Multiple choice. Circle the letter of the most correct answer.
1
Specialised cells in the right atrium of the heart sends an electrical
impulse which causes the heart to beat. The group of specialised
cells is called the:
(A) tricuspid valve
(B) AV junction
(C) bicuspid valve
(D) sinoatrial node.
2
Ultrahigh molecular weight polyethylene (UHMWPE) is used in:
(A) all artificial heart valves
(B) replacement silicone joints
(C) large replacement joints
(D) pacemakers.
3
The above diagram demonstrates a medical technique used to restore
blood flow in a hardened artery. The medical technique is:
(A) balloon angioplasty
(B) stenting
(C) cardiac catheterisation
(D) thrombectomy.
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19
4
Which type of synovial joints do elbow and knee joints classify as?
(A) hinge joints
(B) pivot joints
(C) ball and socket joints
(D) sliding joints
5
The cochlear implant is an invention which:
(A) replaces joints in the fingers and toes
(B) aids hearing
(C) replaces diseased heart valves
(D) aids heart beat.
6
The invention that allowed heart surgery to take place successfully
was:
(A) pacemakers
(B) artificial heart valves
(C) the heart lung machine
(D) the artificial lung.
7
C
B
A
The labels A, B and C on the above diagram of the heart are
respectively:
(A) pulmonary artery, bicuspid valve, right atrium
(B) right ventricle, bicuspid valve, pulmonary artery
(C) left ventricle, tricuspid valve, pulmonary artery
(D) right atrium, tricuspid valve, aorta.
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Medical technology – bionics
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8
Which of the following is not a non–invasive medical technique?
(A) X–ray
(B) Magnetic resonance imaging
(C) Keyhole surgery
(D) Ultrasound
9
Silicone, titanium and chromium are useful material for implants
because:
(A) they are all light weight
(B) they are all biocompatible
(C) they are all durable
(D) all of the above.
10 The heart valve disease which results in reduced blood flow to the
body is:
(A) insufficiency
(B) arhythmia
(C) atherosclerosis
(D) fibrillation.
Part B Short answer questions
11 a) Explain the role of the skeletal system in humans.
_________________________________________________
_________________________________________________
b) What is the function of cartilage in synovial joints?
_________________________________________________
c) What two structures are joined by ligaments?
_________________________________________________
d) What two structures are joined by tendons?
_________________________________________________
e) Give one reason why synovial joints may need replacing in
humans.
_________________________________________________
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21
12 a) Explain the action of heart valves in the heart.
__________________________________________________
__________________________________________________
b) Draw an example of an artificial heart valve in the space below.
c) Explain how the artificial heart valve you drew above acts in the
same way as a heart valve.
__________________________________________________
__________________________________________________
13 a) Explain the role of the circulatory system.
__________________________________________________
__________________________________________________
b) Explain how cardiopulmonary resuscitation can maintain life
when the heart has stopped beating.
__________________________________________________
__________________________________________________
__________________________________________________
14 a) Identify two life support systems used in hospitals.
__________________________________________________
b) Choose and circle the name of one of the life support systems
stated above. Explain the role of this life support system in
maintaining human life.
__________________________________________________
__________________________________________________
c) Outline one surgical procedure which can take place
successfully as a result of this life support system.
__________________________________________________
__________________________________________________
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Medical technology – bionics
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15 a) Define the term non–invasive with regards to diagnostic medical
techniques.
_________________________________________________
_________________________________________________
b) Define the term minimally invasive in terms of medical
techniques.
_________________________________________________
_________________________________________________
c) Outline the advantages and disadvantages of key hole surgery.
_________________________________________________
_________________________________________________
_________________________________________________
Part C Extended answer questions
16 a) Explain why the heart makes a double beat sound.
_________________________________________________
_________________________________________________
_________________________________________________
b) Explain two conditions which can cause abnormal heartbeat.
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
c) Explain how a pacemaker implant can help maintain a regular
heartbeat.
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
Part 6: Peek-a-boo
23
17
B
A
a) What ball and socket joint does the above artificial joint replace
in humans?
__________________________________________________
b) What is the artificial thigh piece labelled ‘A’ above made of?
__________________________________________________
c) What is the structure labelled ‘B’ in the above diagram made of?
__________________________________________________
d) Explain why the structure labeled ‘B’ degrades faster than the
structure labeled ‘A’ in the above diagram.
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
e) Explain how uncemented implants attach to bone for stability.
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
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Medical technology – bionics
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18 a) Explain the term atherosclerosis.
_________________________________________________
_________________________________________________
b) What causes atherosclerosis?
_________________________________________________
_________________________________________________
c) How can atherosclerosis be prevented?
_________________________________________________
_________________________________________________
d) Explain two medical procedures which restore blood flow to and
from the heart through arteries affected by atherosclerosis.
Accompany each explanation with a diagram demonstrating the
procedure.
i)
________________________
________________________
________________________
________________________
________________________
________________________
ii) ________________________
________________________
________________________
________________________
________________________
________________________
Part 6: Peek-a-boo
25
Student evaluation
Name: _______________________
Location: ______________________
We need your input! Can you please complete this short evaluation to
provide us with information about this module. This information will
help us to improve the design of these materials for future publications.
1
Did you find the information in the module clear and easy to
understand?
_____________________________________________________
2
What did you most like learning about? Why?
_____________________________________________________
_____________________________________________________
3
Which sort of learning activity did you enjoy the most? Why?
_____________________________________________________
_____________________________________________________
4
Did you complete the module within 30 hours? (Please indicate the
approximate length of time spent on the module.)
_____________________________________________________
_____________________________________________________
5
Do you have access to the appropriate resources? eg. a computer,
the internet, scientific equipment, chemicals, people that can provide
information and help with understanding science
_____________________________________________________
_____________________________________________________
Please return this information to your teacher, who will pass it along to
the materials developers at OTEN – DE.
SSCHSC43169 Medical technologybionics
Learning Materials Production
Open Training and Education Network – Distance Education
NSW Department of Education and Training