OCR_B5_revision

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Biology Revision
B5 The Living Body
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5a In good shape

Skeletons

No skeleton – e.g. worms

Exoskeleton – e.g. insect made of chitin

Endoskeleton – e.g. shark made of cartilage; human bone
with some cartilage

Advantages of endoskeleton:
1.
Framework of body
2.
Can grow with body
3.
Easy to attach muscles
4.
Flexibility
Human skeleton starts as
cartilage by is ossified by
the addition of calcium &
phosphorus. Amount of
cartilage present
determines growth stage
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5a In good shape

Long bone structure:

Head covering of cartilage

Shaft, bone marrow with blood vessels

Cartilage & bone are living tissue

Bones are strong but easily broken

Types of fractures:

Simple

Compound

Green stick
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5a In good shape

Joints

Where 2 or more bones meet

Joined by ligaments

Bones moved by muscles, attached by tendons

Synovial joints e.g. ball & socket, hinge
Advantages &
disadvantages of
joint
replacement?
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5a In good shape

The arm

Biceps & triceps are antagonistic muscles

Arm is like a lever:

Biceps contract, triceps relax -> arm raises
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5b The vital pump

Circulatory Systems

None – e.g. amoeba

Open – e.g. insects

Closed – single e.g. fish , 2 chambered heart

Double e.g. mammals, 4 chambered heart

Historical contributions about circulatory system:

Galen – 200AD – believed blood flowed between heart &
liver

Harvey – 1628 – discovered blood vessels, valves & high
pressure blood flows away from heart in arteries
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5b The vital pump

Cardiac Cycle – controlled by SAN & AVN

ECG

Effect of adrenaline?

Exercise?
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5c Running repairs

Heart Conditions/Diseases
Condition

Effect
Treatment
Irregular heart beat
Pacemaker
Hole in heart
Surgery
Damaged or weak
valves
Replacement with
artificial valves
Blocked coronary
artery
Bypass surgery
Heart attack
Transplant –
disadvantages?
Lifestyle risk factors– diet, alcohol smoking, stress, drugs
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5c Running repairs

Blood components

Blood groups: A, B, AB, O

Rhesus positive & negative

Agglutinins – markers on the surface
of red blood cells which make them Clump
if they contact the corresponding antigen:
Blood group
Agglutinin on
surface
Antibodies in
blood
Can accept
blood from
A
A
Anti-B
A or O
B
B
Anti-A
B or O
AB
A&B
None
Any
O
None
Anti-A & Anti-B
O
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5c Running repairs

Blood donation – cards for everyone? Religious objections?
Blood Clotting occurs:
1. When blood vessels are damaged
2. When blood comes into contact with air
3. To prevent too much blood being lost
4. To prevent pathogens entering through wounds



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
Vitamins K & C are needed for healthy blood clotting
Alcohol & cranberries slow it down
Anti-coagulant drugs e.g. warfarin, heparin & aspirin reduce it
Haemophilia is an inherited disease where a faulty protein stops
blood clotting
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5d Breath of life
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Gas Exchange

Simple organisms e.g. amoeba through skin

Complex organisms through specialist organs

Fish gills
Respiratory System
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5d Breath of life

Breathing
Volume of chest cavity
increases, pressure in
lungs falls
Volume in chest cavity
decreases, pressure in
lungs rises
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5d Breath of life

Measuring Breathing

Tidal air/volume – volume of air in a normal breath

Vital capacity – maximum volume breathed in & out

Residual air/volume – air
that remains in lungs

Respiratory Diseases

Industrial e.g. asbestosis

Genetic e.g. cystic fibrosis

Lifestyle e.g. lung cancer
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Pathogenic e.g. pneumonia
Asthma – irritated bronchioles narrow,
muscles tighten, more mucus produced
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5e Waste Disposal

Excretion – getting rid of waste e.g. CO2, urea, sweat

Defecation – getting rid of solid waste through the anus

Excretory organs: lungs, kidneys, liver, skin

Skin structure:

Excess water & salt are
excreted as sweat, which
evaporates
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5e Waste Disposal

Kidneys
Ultrafiltration – at bowman’s capsule – small molecules squeezed out
under pressure
Selective reabsorption – in tubules & loop of Henle – useful substances
reabsorbed into blood
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5e Waste Disposal
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ADH – controls reabsorption of water in kidneys

Made in pituitary gland

Negative feedback:

Water content low -> ADH released -> nephron tubules more
permeable -> normal water level
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Dialysis Machine

Waste diffuses from blood into
dialysis fluid

Sodium & glucose in blood
replaced
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5f Life goes on
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Fertilisation – fusion of a male & female gamete

Reproductive systems:
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5f Life goes on
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Menstrual Cycle
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Day 1-5 – menstruation

Day 14 – ovulation
Hormone
Where
Made
Effect
FSH
Pituitary
Stimulates egg to
ripen & oestrogen
release
Oestrogen
Ovary
Uterus lining
thickens, LH
released
LH
Pituitary
Ovulation
Progesterone
Ovary/c
orpus
luteum
Preserve uterus
lining
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5f Life goes on
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Infertility

Fertility drugs – FSH injected to stimulate egg release

Artificial insemination

Egg donation – problem? Only has genes from one parent
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Ovary transplant
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Surrogacy – problem? Emotional attachment

IVF – problem? low success rate, twins/triplets more likely

Foetal Screening – for health of baby

Ultrasound
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Anmiocentesis – tests cells from amniotic fluid using hypodermic needle,
Ethical issues? Can cause miscarriage (1 in 200), termination?
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5g New for old

Organ Donation

Biological replacement e.g. blood, cornea, heart, lungs,
kidney & bone marrow

Organs must be: healthy, right size & age, tissue matched

Can be from living donors e.g. kidneys or dead donors if
they cannot regain consciousness & breath unaided

Mechanical replacement e.g. Kidney, knee & hip joint,
heart, eye lens
Problems with mechanical
Problems with Biological
Size
Shortage of donors
Power supply
Tissue match/
immunosuppresants
Material used (non wearing)
Rejection
Body reactions e.g. allergic
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5h Size matters

Growth – animals grow in the early stages of life, plants grow
continually in areas called meristems e.g. shoot tips

New cells for growth made by mitosis

Human growth stages:
1.
Infancy (up to 2)
2.
Childhood (2 -11)
3.
Puberty (11-15)
4.
Adulthood (15 – 65)
5.
Old age (over 65)
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Problems of living longer?
Growth is measured as gain in
height & mass
Determined by:
Genes
Diet
Exercise
Hormones
Health/disease
Human growth hormone – made in pituitary
gland – releases energy for growth from fat
stores, stimulates growth of long bones
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