h. Transport
14/03/2011 07:23:00
Objectives:
h. Transport
2.49 understand why simple, unicellular organisms can rely on diffusion for
movement of substances in and out of cells.
2.50 understand the need for a transport system in multicellular organisms
2.57 recall the composition of the blood: red blood cells, white blood cells,
platelets and plasma
2.58 understand the role of plasma in the transport of carbon dioxide, digested
food, urea, hormones and heat energy
2.59 describe the adaptations of red blood cells for the transport of oxygen,
including shape, structure and the presence of haemoglobin
2.60 describe how the immune system responds to disease using white blood
cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing
antibodies specific to the pathogen.
2.61 understand that vaccination results in the manufacture of memory cells,
which enable future antibody production to the pathogen to occur sooner,
faster and in greater quantity.
2.62 recall that platelets are involved in blood clotting, which prevents blood
loss and the entry of microorganisms
2.63 describe the structure of the heart and how it functions
2.64 understand that the heart rate changes during exercise and under the
influence of adrenaline
2.65 describe the structure of arteries, veins and capillaries and understand
their roles
2.66 recall the general plan of the circulation system to include the blood
vessels to and from the heart, the lungs, the liver and the kidneys.
2.49 Diffusion
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2.49 understand why simple, unicellular organisms can rely on diffusion for
movement of substances in and out of cells.
Simple, unicellular organisms can rely on diffusion to move substances in and out
of their cells because they have a large surface area to volume ratio.
Small organisms = Large surface area to volume ratio.
Large organisms = Small surface area to volume ratio.
To do:
Visit the website:
http://esminfo.prenhall.com/science/BiologyArchive/lectureanimations/closerlo
ok/cellsurface.html
Use the animation to fill in the table below:
Length of side
Total surface area Volume
Surface area/volume
2m
24
8
3.00
4m
96
64
1.50
6m
216
216
1
8m
384
512
0.75
10m
600
1000
0.60
In your own words describe what happens to the surface area : volume as the
length of the side of the “cell” is increased by 2m.
What are the implications of this for the cell?
2.50 Transport System
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2.50 understand the need for a transport system in multicellular
In the previous objective you learnt that as cells become bigger their surface
area : volume decreased. This means that the cell no longer has sufficient
surface area for diffusion to provide the volume within the cell with all it needs.
When cells get to a certain size they will divide. By dividing they once again
increase their surface area : volume. The organism is no longer unicellular but is
becoming multicellular.
To do:
View the website:
http://www.brown.edu/Courses/BI0020_Miller/week/10/web-1/4-2-2007_1020-26/Chapter_41/Present/Animations/41_A01/41_A01s.html
You will go through this animation with your teacher (it is very high level – you
just need to understand the basics).
As you watch the animation, pause to answer the following questions:
1. As the cube increases in size, describe the relationship between the increase
in volume and the increase in surface area.
2. In the animation, two cubes the same size are compared. One stays as a single
cube, the other divides into smaller cubes. Describe the effect dividing the
large cube into smaller cubes has on the following:
 surface area
 volume
 surface area : volume
3. What does the rate of diffusion across the cell membrane depend on?
4. What does the rate of nutrients needed and waste products produced depend
on?
5. What happens (in terms of diffusion) as the cell increases in size?
6. Name the metabolic process that uses oxygen and produces carbon dioxide.
7. To meet their requirements how are some structures in the body adapted to
carry out their function (e.g. alveoli in lungs and villi in small intestine)?
Cell division overcomes the problem of surface area : volume ….
But they have now created another problem?
How do cells the cells in the centre of a multicellular organism obtain the
substances they need to survive?
2.57 Blood Composition
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2.57 recall the composition of the blood: red blood cells, white blood cells,
platelets and plasma
Ref:
Pg. 59
7.13 “Blood consists of cells floating in plasma”
To do:
View the animation:
http://www.youtube.com/watch?v=CRh_dAzXuoU
This video is an introduction to many of the things we will learn in this topic in
future objectives.
Watch it through once, then watch it again and answer the following questions:
1. Name the yellowish, liquid part of blood.
2. What is the main component of this liquid?
3. Which substances might you find dissolved in it for transport around the
body?
4. Name the three types of cells you will find in blood.
5. What is the main function of the red blood cells?
6. What is the function of the white blood cells?
7. What important function do platelets carry out?
Introduction to Blood
Most adults have 4 to 6L of blood.
Blood is composed of 4 components, as shown in this diagram:
Blood Cells
Erythrocytes = red blood cells
Platelets = cell fragments
Leukocytes = white blood cells (phagocytes and lymphocytes)
Questions
1. This test tube contains blood, which was left to stand overnight. The cells
sank to the bottom of the tube.
(a) On the diagram, label the layers of separated blood. (1)
(b) Use words from the box to complete the table. (3)
carries glucose
form a scab
carries oxygen
part of blood
plasma
platelet
white blood cell
function
fights bacteria
helps
2.58 Plasma
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2.58 understand the role of plasma in the transport of carbon dioxide, digested
food, urea, hormones and heat energy
Ref:
Pg. 61-62
7.17 “Many substances are transported by the blood”
To do:
 Read the relevant pages in the textbook and make brief notes under each of
the following titles:
Carbon Dioxide
Digested Food
Urea
Hormones
Heat Energy
2.59 Red Blood Cells
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2.59 describe the adaptations of red blood cells for the transport of oxygen,
including shape, structure and the presence of haemoglobin.
Ref:
Pg. 59-60
7.14 “Red Blood Cells carry oxygen”
To do:
Draw a diagram of a large red blood cell in your books. Using the notes below,
annotate your diagram to relate the structure of red blood cells to their
function.
Red Blood Cells
Erythrocytes (red blood cells) do not contain a nucleus, which results in them
having the characteristics biconcave shape (the sunken centre is where the
nucleus used to be). A pigment called haemoglobin combines with the oxygen in
the lungs to form oxyhaemoglobin.
The main function of RBC is the transport of respiratory gases. Oxygen is
picked up from the lungs and delivered to the tissues. Carbon dioxide is picked
up from respiring cells and transported to the lungs to be exhaled.
Oxygen is carried in RBC attached to the protein haemoglobin. Haemoglobin
contains iron which the oxygen molecule binds to. RBC have specific features
(listed below) that make it efficient in absorbing and transporting respiratory
gasses:
 They are small - They are much smaller than most other cells in the body.
This means that all the haemoglobin molecules are close to the surface,
allowing oxygen to be picked up and release rapidly.
 Shape - RBC are biconcave shapes discs. It allows the cell to contain a lot of
haemoglobin while still allowing efficient diffusion through the plasma
membrane.
 Organelles – RBC do not contain either nuclei or mitochondria. This allows
more space inside the cell for haemoglobin. As they do not contain a nucleus
there is nothing to control the functioning of a RBC and so they usually only
live for approximately 120 days. A lack of mitochondria means they cannot
carry out aerobic respiration. This also prevents them from consuming the
oxygen they are transporting to other cells.
Questions
1. Draw one line from each blood part to its function. (3)
blood part
function
red blood cells
help clot the blood
white blood cells
transports urea
platelets
transport oxygen
plasma
destroy bacteria
2. Blood is a mixture of plasma, white blood cells, red blood cells and platelets.
The diagram shows a sample of blood,
(a) How many white blood cells are shown? (1)
(b) Use words from the box to label parts A and B on the diagram. (4)
cytoplasm
nucleus
haemoglobin
membrane
(c) Which part of the blood carries oxygen? (1)
3. Red blood cells contain haemoglobin to carry oxygen.
State two other ways in which a red blood cell is adapted to carry out its
function. (2)
4. The word equation for the reaction between oxygen and haemoglobin is shown
below.
oxygen + haemoglobin
oxyhaemoglobin
(a) In which organ is oxyhaemoglobin formed? (1)
(b) Explain why it is important that the reaction is reversible. (2)
5. The diagram shows the site for the exchange of substances between the
blood and body cells.
(a) Name the type of blood vessel shown in the diagram. (1)
(b) Cell ‘A’ is releasing oxygen. Name cell ‘A’. (1)
2.60 White blood cells
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2.60 describe how the immune system responds to disease using white blood
cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing
antibodies specific to the pathogen.
Ref:
Pg. 60
7.15 “White blood cells fight infection”
Pg. 139
13.9 “The body has many defences against infection”
Pg. 140
13.10 “Antibodies are specific”
Phagocytosis
Phagocytes are large white blood cells that engulf foreign material to destroy
it. They often engulf and destroy invading bacteria.
To do:
View the websites:
http://www.edumedia.fr/a82_l2-phagocytosis.html
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__phagocytosis.
html
In your books draw a series of pictures/ diagrams/ cartoons to illustrate
phagocytosis. Use the stages below to annotate your diagram:
Phagocytosis occurs by the following process:
1. The pathogen becomes surrounded by cytoplasm.
2.
3.
4.
5.
Pathogen is ingested (engulfed).
Lysosome enzymes released into packet with pathogen.
Digestion of pathogen.
Release of digestion products from the cell.
Antibody Production
An antibody is a protein found in the blood plasma. A particular region of the
antibody forms an antigen-binding site, which attached to the antigen molecule.
The antibody’s structure matches its antigen much as a lock fits a specific key.
An antigen is a something the body sees as being foreign and so will launch an
immune response against it.
Antibody Actions
All antibodies act in some way to disable antigens. Actions of antibodies
include:
Neutralising the antigen.
The reaction of the antibody with antigen blocks or neutralises some bacterial
toxins and prevents attachment of some viruses to body cells.
Immobilising bacteria.
If antibodies form against antigens on the cilia or flagella of bacteria, the
antigen-antibody reaction may cause the bacteria to lose their motility, which
limits their spread into nearby tissues.
Clumping
Because antibodies may have two or more sites for binding to antigens, the
antigen-antibody reaction may cross-link pathogens to one another, causing
them to clump together). This makes phagocytosis easier.
View the website:
http://www.yteach.ie/page.php/resources/view_all?id=antigen_amoeboid_move
ment_bone_marrow_lysosomal_enzymes_lysozyme_pathogenic_factor_plasma_
cells_immune_system_lysosomes_b_cells_b_lymphocytes_phagocytosis_t_lymp
hocytes_granulocytes_page_6&from=search
Teacher access only
View the Youtube video:
http://www.youtube.com/watch?v=lrYlZJiuf18
Here you can see bacteria with antigens on their surface.
Some of the bacteria are landing on cells and could infect them.
There are antibodies present which block the antigen sites – this stops the
bacteria from infecting the cells.
A large phagocytes then comes along and engulfs the bacteria.
Questions
1. The diagrams show two different types of white blood cells in action.
Describe how cells A and B defend the body against bacteria. (4)
2.61 Vaccination
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2.61 understand that vaccination results in the manufacture of memory cells,
which enable future antibody production to the pathogen to occur sooner,
faster and in greater quantity.
Ref:
Pg. 140
13.11 “Lymphocytes multiply when their pathogen is present”
13.12 “Memory Cells make you Immune”
The concept behind immunization:
View the animation: “Vaccination”
http://resources.schoolscience.co.uk/abpi/immune/immanim3.htm
View the animation:
http://video.about.com/pediatrics/Vaccination.htm
View the animation: “Primary and Secondary Immune Responses – the concept of
immunization”
http://www.yteach.ie/page.php/resources/view_all?id=antigen_b_cell_central_l
ymphatic_organ_free_radical_pathogen_peripheral_lymphatic_organ_phagocyt
osis_somatic_recombination_specificity_t_cell_immunity_tc_lymphocytes_cyto
toxic_t_prion_protein_glycoprotein_page_5&from=search
Teacher access only.
As you watch the animation, answer the following questions:
1. What will happen to a B-cell (lymphocyte) when it encounters an antigen?
2. Name the two types of B-cells produced.
3. What are the different roles of the two types of B-cells?
4. What do you notice about the difference in the primary and secondary
immune responses?
5. What is the explanation in the difference behind the time for immune
response?
Using the graph above to write a paragraph explaining the concept of
vaccination in your own words.
Vaccination
1. A weakened or dead version of the pathogen is introduced to the body
(usually via an injection).
2. The body will initiate the primary immune response.
3. B-lymphocytes will multiply to become plasma cells and memory cells.
4. The plasma cells will produce antibodies to combat the introduction of the
pathogen.
5. The memory cells will remain in the blood, if they ever encounter the same
pathogen again the immune response will occur sooner, faster and in greater
quantity.
To do:
Using animations and the notes above, in your greenbooks draw a series of
diagrams or a flow chart to illustrate the process of vaccination.
2.62 Platelets & Clotting
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2.62 recall that platelets are involved in blood clotting, which prevents blood
loss and the entry of microorganisms
Ref:
Pg. 61
7.16 “Platelets help blood to clot”
View the animation: “Blood Clotting”
http://www.footprints-science.co.uk/Bloodclotting.htm
This animation does not have an explanation. Jot down notes as we watch the
animation.
View the second animation:
http://adam.about.com/care/Blood-clotting-animation.htm
This animation is more detailed with explanations of the process occurring.
Blood Clotting
We cannot lose too much blood or we would not have sufficient red blood cells
to carry oxygen around our bodies. When we injure a blood vessel, the clotting
process occurs very quickly. This helps to prevent further blood loss and also
prevents microorganisms from entering at the site of injury.
The Process
1. Blood vessel is damaged
2. Platelets stick to damaged tissue
3. Blood clotting factors convert fibrinogen to fibren,
4. Platelets, fibrin and blood cells form a clot.
Questions
1. The diagram shows a blood clot.
(a) Give TWO functions of a blood clot. (2)
(b) Suggest the function of the fibrin fibres. (1)
(c) How does a blood clot form? (2)
2. Scientists investigated the time it took for samples of human blood to clot at
different temperatures.
The results are shown in the table.
Temperature (°C)
5
15
Time for blood to
clot (s)
46 34
25 35 45
26 16
25
Use the information from the table and your knowledge to answer the following
questions.
(a) What does the graph show about the effect of temperature on the time it
takes for blood to clot? (2)
(b) How does your answer to part (a) suggest that enzymes are involved in the
clotting process? (1)
(c) Suggest the effect of a temperature of 75°C on the clotting process.
Give a reason for your answer. (2)
3. The diagram shows an artery, capillary and a vein in a muscle. A blood clot
has completely blocked the artery, stopping the flow of blood.
(a) Name ONE useful substance which does not reach the capillaries in the
muscle. (1)
(b) Name ONE waste substance which does not leave the muscle. (1)
2.63 Heart Structure
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2.63 describe the structure of the heart and how it functions
Ref:
Pg. 54
7.2 “Mammals have double circulatory systems”
7.3 “Blood becomes oxygenated and deoxygenated”
7.4 “Heart Structure is related to function”
Pg. 55
7.5 “Coronary arteries supply heart muscle”
Pg. 56
7.6 “The heart beats regularly”
7.7 “Blood flows one way through heart valves”
To do:
1. The following are a list of website which provide information and animations
on the structure and function of the heart.
2. Visit the animations in the order they are listed.
3. Some animations you simple need to watch and listen.
4. There are questions to complete for one of the animations towards the end –
by this stage you should know your way round the heart pretty well.
Websites to Visit
http://www.hybridmedicalanimation.com/anim_bloodflow.html
This animation shows an almost life-like heart pumping
May take time to load – if so – I will show you this on the white board.
http://www.kscience.co.uk/animations/heart.swf
Very basic – some labels provided.
Shows flow of deoxygenated blood through right hand side of heart and
oxygenated blood through left hand side of heart.
http://health.howstuffworks.com/adam-200083.htm
Excellent animation – watch this one more than once.
Listen carefully to all the information.
http://www.smm.org/heart/heart/top.html
Order in which to view website
1. Find the heart with a virtual stethoscope
2. Interactive – view the heart with interactive labels (click on – “Interactive
Labels On”
3. Animation – your heart valves at work – simply follow the flow of blood flow
through the right and left side of the heart and watch what happens to the
valves.
4. Animation – see the flow of blood to and from the heart
http://www.mydr.com.au/heart-stroke/animation-how-your-heart-pumps
Watch the animation.
By now you should be recognizing many of the structures and the direction in
which blood flows.
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.html
Excellent animation.
Listen careful to the explanations of how the heart functions and answer the
questions below:
Heart Structure
1. What type of tissue is the heart made from?
2. What separates the right and left hand sides of the heart?
3. How many chambers are in the heart? List the names of these chambers.
4. How many valves are in the heart?
5. What is the function of these valves?
6. To where does the right side of the heart pump blood? What is the name of
the vessel that carries blood away from the right hand side?
7. To where does the left side of the heart pump blood? What is the name of
the vessel that carries blood away from the left hand side?
You will be given a handout with a diagram of the heart (the same as the
diagram below).
Label as many structures as you can
Using BLUE ARROWS - show the flow of deoxygenated blood through the right
hand side of the heart.
Using RED ARROWS – show the flow of oxygenated blood through the left
hand side of the heart.
Add in any notes you think are important.
1. Superior Aorta
9. Pulmonary artery
2. Superior Vena cava
3. Pulmonary artery
4. Pulmonary vein
10. Pulmonary vein
11. Left attrium
5. Right atrium
12. Bicuspid valve
6. Tricuspid valve
13. Semilunar valve
7. Right ventricle
14. Left ventricle
8. Inferior vena cava
15. Inferior aorta
RIGHT hand side of the Heart
LEFT hand side of the Heart
1.
1.
2.
3.
4.
5.
6.
2.
3.
4.
5.
6.
Deoxygenated Blood – RIGHT hand side of heart
To which chamber does deoxygenated blood enter from the body? In which
vessel does it enter?
How does the right atrium move blood into the right ventricle?
What valve is between the right atrium and ventricle?
Why does the tricuspid valve close when the ventricle is full?
When the right ventricle fills and contracts, which valve needs to open and to
which vessel does the blood flow? Where does this vessel take the blood?
Why does the pulmonary valve close quickly?
Oxygenated Blood – LEFT hand side of heart
Through which vessels does oxygenated blood return to the heart?
To which chamber does oxygenated blood return?
Once the atrium is filled it will contract and force blood through the
BISCUSPID valve into which chamber?
Why must the bicuspid valve close when the ventricle is full?
When the left ventricle contracts, which valve opens and into which vessel is
oxygenated blood pumped?
Why does the aortic valve need to close quickly?
Questions
1. The diagram shows the heart as the atria contract.
A.
C.
B.
(a) Label parts A, B and C. (3)
(b) Put one arrow in the left atrium to show the direction of blood flow. (1)
(c) When a ventricle contracts, it forces the valve between itself and the
atrium upwards.
(i) Suggest what happens to the heart tendons when a ventricle contracts. (1)
(ii)
Why are the heart tendons important? (1)
(d) Pressure changes in the heart open and close valves. Explain what happens as
a result of the left ventricle contracting. Refer to pressure differences and
valve changes in your answer. (4)
2. The diagram shows a human heart.
B.
A.
(a) Label parts A and B. (2)
(b) A woman’s heart rate was measured and recorded on a graph.
(i) What was the fastest rate recorded? (1)
(ii) Suggest a reason why the woman’s heart rate increased. (1)
(iii) How long did it take for her heart rate to return to normal from its fastest
rate? (1)
(c) The woman went to hospital to have the activity of her heart checked by a
machine.
This is what the doctor saw on the monitor screen. He pointed out the pattern
he saw when the atria contract and when the ventricles contract.
(i) On the diagram of the monitor screen, draw an arrow pointing to another
place which shows the atria contracting. (1)
(ii) How many heart beats are shown on the screen? (1)
3. The diagram shows the human heart during a heartbeat. Blood vessels which
take blood to and from X are included.
(a) Label vessel A and chamber C. (2)
(b) Name X. (1)
(c) Name the chamber of the heart which contracts to move blood into organ X.
(1)
(d) Complete the table to show the relative amounts of oxygen and carbon
dioxide in blood vessel A compared to blood vessel B.
Write one word in each box from the list below. (2)
more
less
equal
in vessel A
relative amount of
oxygen in blood
relative amount of
carbon dioxide in blood
(e) (i) What is the function of a valve? (1)
in vessel B
(ii) The bicuspid valve in the diagram is closed. Explain how this valve is opened.
(2)
(f) The heart is supplied with blood by the coronary artery.
Eating a lot of animal fat can have an extremely damaging effect on this artery.
Explain how damage to this artery affects the working of the heart. (3)
4. The diagram shows a human heart.
(a) Name the type of tissue labelled A. (1)
(b) What is the function of the valves in the heart? (1)
(c) Suggest why arteries have thicker walls than veins. (1)
(d) Suggest why capillaries have very thin walls. (1)
(e) Describe the differences between blood in the aorta and in the vena cava.(3)
5. The diagram shows a section through the heart during contraction of the
atria.
Describe the changes that occur in the heart which cause blood to enter the
arteries.
Refer to the action of the ventricles and the valves. (4)
6. Diagrams 1 and 2 show a section through the heart.
Diagram 1 shows two valves.
(a) Explain what would happen in diagram 2 to these valves as the ventricles
contract. (1)
(b) Draw arrow heads on lines X and Y to show the direction of blood flow.(1)
(c) The diagram shows the heart and associated blood vessels.
Explain why arteriosclerosis in the coronary arteries at point X can cause the
heart muscle in the shaded area to stop beating. (2)
(d) The circulation of blood round part of the body is shown below. The arrows
next to blood vessels A and B show the direction of the blood flow.
On the diagram, draw arrows to show the direction of blood flow in vessels C
and D. (2)
(e) Each labelled blood vessel is either an artery or a vein. Tick the correct box
for each blood vessel. (2)
One has been done for you.
blood vessel
A
B
C
D
(f) Give the name of organ X. (1)
artery
vein
2.64 Heart Rate
14/03/2011 07:23:00
2.64 understand that the heart rate changes during exercise and under the
influence of adrenaline
To do:
Answer the following questions to help you understand the effects of exercise
on heart rate:
1. What happens to your heart rate as you exercise?
2. Which important process are your muscles carrying out during exercise?
3. What two substances must be supplied to the working muscles?
4. How are these two substances transported by the blood?
5. What waste products are produced by the respiring muscle cells?
6. Why must waste products be removed?
7. What type of respiration will occur if the cells do not receive enough oxygen
and what is produced in this type of respiration?
Use the information above to write a summary paragraph about the relationship
between heart rate and exercise.
Adrenaline
 Adrenaline is a hormone.




Adrenaline is known as the “fight-or-flight” hormone.
A hormone is a chemical messenger released from a gland in one part of the
body and travels in the blood stream to its target organ, which will bring
about a response to the hormone.
Adrenaline is released by the adrenal glands, which sit just on top of the
kidneys.
Adrenaline has many effects on the body.
List some of the effects of adrenaline on the body.
Heart and Exercise Questions
1. Jim is an athlete.
His pulse rate was measured before, during and after a 15 minute training run.
The results are shown on the graph.
(a) Describe how his pulse rate increases during the run. (1)
(b) After his run had ended, how long did it take for Jim’s pulse to return to its
rate before the run?
(1)
2.64 Blood Vessels
14/03/2011 07:23:00
2.65 describe the structure of arteries, veins and capillaries and understand
their roles
Ref:
Pg. 57
Pg. 58
7.8
There are three kinds of blood vessels
7.9 Arteries have thick elastic walls
7.10 Capillaries are very narrow, with thin walls
Diagram 7.5 Section through three types of blood vessels
7.11
Veins have one-way valves
Diagram 7.7 Valves in Veins
Table 7.1 Arteries, veins and capillaries
Arteries
Arteries carry blood AWAY from the heart to every tissue in the body.
They have thick, elastic walls to withstand the high pressure of blood from the
heart.
Vasoconstriction and Vasodilation
The smaller arterioles are muscular and can contract (vasoconstriction) to close
off the capillaries or relax (vasodilation) to open up the capillaries. These
changes are happening constantly under the involuntary control of the brain, and
are most obvious in the capillaries of the skin, causing the skin to change colour
from pink (arterioles vasodilate) to blue (arterioles vasoconstrict).
Veins
Veins carry blood from every tissue in the body bringing it back to VISIT the
heart.
It is at low pressure inside veins and moving slowly. Veins therefore don’t need
thick walls and they have a larger lumen than arteries, to reduce the resistance
to flow.
They also have semi-lunar valves to stop the blood flowing backwards. It is
particularly difficult for blood to flow upwards through the legs to heart, and
the flow is helped by contractions of the leg and abdominal muscles:
Extra info – no need to learn
The body relies on constant contraction of these muscles to get the blood back
to the heart, and this explains why soldiers standing still on parade for long
periods can faint, and why sitting still on a long flight can cause swelling of the
ankles and Deep Vein Thrombosis (DVT or “economy class syndrome”), where
small blood clots collect in the legs.
Capillaries
Capillaries are where the transported substances actually enter and leave the
blood.
No exchange of materials takes place in the arteries and veins, whose walls are
too thick and impermeable.
Capillaries are very narrow and thin-walled, but there are a vast number of
them, so they have a huge surface area: volume ratio, helping rapid DIFFUSION
of substances between blood and cells. Capillaries are arranged in networks
called capillary beds feeding a group of cells, and no cell in the body is more
than 2 cells away from a capillary.
Questions
1. The diagram shows a vein being injected.
(a) Label X. (1)
(b) Draw an arrow inside the vein to show the direction of blood flow. (1)
(c) Doctors inject different substances into the veins of their patients.
Suggest why doctors inject into veins rather than arteries. (1)
(d) Explain why a doctor might inject a patient with insulin. (2)
(e) Suggest why a doctor might inject a patient with morphine (heroin). (1)
2. The diagram shows a kidney with a ureter and two blood vessels.
(a) Name artery A. (1)
(b) What evidence from the diagram shows that A is an artery and not a vein?(1)
(c) Name the carbohydrate found in the blood in A and B but not in the ureter.
(1)
(d) Which part, labelled in the diagram, contains most urea? (1)
3. The diagram shows sections through an artery and a vein.
(a) Describe one similarity, shown in the diagram, between an artery and a vein.
(1)
(b) Describe one difference, shown in the diagram, between an artery and a
vein. (1)
(c) Describe the function of the muscle in the artery. (2)
4. The diagram shows a side view through a valve in a vein. (2)
Describe what happens to the valve when blood begins to move from
A to B
B to A
5. The diagram shows cross sections of three types of blood vessel.
On the diagram above, label the artery, the capillary and the vein. (2)
2.66 Circulatory System
14/03/2011 07:23:00
2.66 recall the general plan of the circulation system to include the blood
vessels to and from the heart, the lungs, the liver and the kidneys.
Ref:
Pg. 58
7.12
Pg. 59
Diagram 7.8 Plan of the main blood vessels in the human body
Each organ has its own blood supply
To do:
Read the following information to help you label the diagram below.
* you do not need to learn all the statements below, it is just to help you answer
the questions
Blood Vessels from the heart
Aorta  carries oxygenated blood away from heart to the entire body.
Pulmonary arteries  carry deoxygenated blood away from heart to the lungs
to pick up oxygen. These are the only arteries in the body, which carry
deoxygenated blood.
Blood Vessels to the heart
Vena cava  carries deoxygenated blood back from the body to visit the
heart.
Pulmonary veins  carry oxygenated blood away from the lungs back to visit
the heart. These are the only veins in the body, which carry oxygenated blood.
To and from the liver
Hepatic artery  carries oxygenated blood away from the heart to the liver.
Hepatic vein  carries deoxygenated blood away from the liver to visit the
heart.
Hepatic portal vein  carries all the soluble products of digestion (glucose and
amino acids) from the small intestine where they were absorbed to the liver for
processing.
To and from the kidneys
Renal artery  carries oxygenated blood away from the heart to the kidneys
to be filtered. Urea will be filtered out of the blood by the kidneys.
Renal vein  carries deoxygenated blood away from the kidney to visit the
heart. This blood has been filtered and so will contain less urea.
Questions
1. The circulation of blood round part of the body is shown below. The arrows
next to blood vessels A and B show the direction of the blood flow.
(a) On the diagram, draw arrows to show the direction of blood flow in vessels C
and D. (2)
(b) Each labelled blood vessel is either an artery or a vein. Tick the correct box
for each blood vessel. One has been done for you. (4)
(2)
blood vessel
A
B
C
D
artery
vein
(c) Give the name of organ X. (1)
2. The diagram shows a plan of the circulatory system. The blood vessels are
labelled with letters.
Use the letters on the diagram to complete the sentences in the table.
The first one has been done for you. (4)
Sentence
Letter
The blood vessel named the aorta is
C
The blood vessel containing blood pumped from the right ventricle is
The blood vessel carrying blood with least carbon dioxide is
The blood vessel carrying blood with most amino acids after a meal is
The blood vessel containing blood at lowest pressure is
The first blood vessel to transport inhaled solvents is
3/14/2011 7:23:00 AM