Transcript OCR_B5_revision

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Biology Revision
B5 The Living Body
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5a In good shape
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Skeletons
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No skeleton – e.g. worms
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Exoskeleton – e.g. insect made of chitin
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Endoskeleton – e.g. shark made of cartilage; human bone
with some cartilage
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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
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Long bone structure:
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Head covering of cartilage
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Shaft, bone marrow with blood vessels
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Cartilage & bone are living tissue
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Bones are strong but easily broken
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Types of fractures:
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Simple
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Compound
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Green stick
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5a In good shape
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Joints
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Where 2 or more bones meet
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Joined by ligaments
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Bones moved by muscles, attached by tendons
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Synovial joints e.g. ball & socket, hinge
Advantages &
disadvantages of
joint
replacement?
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5a In good shape
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The arm
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Biceps & triceps are antagonistic muscles
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Arm is like a lever:
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Biceps contract, triceps relax -> arm raises
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5b The vital pump
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Circulatory Systems
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None – e.g. amoeba
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Open – e.g. insects
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Closed – single e.g. fish , 2 chambered heart
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Double e.g. mammals, 4 chambered heart
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Historical contributions about circulatory system:
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Galen – 200AD – believed blood flowed between heart &
liver
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Harvey – 1628 – discovered blood vessels, valves & high
pressure blood flows away from heart in arteries
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5b The vital pump
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Cardiac Cycle – controlled by SAN & AVN
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ECG
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Effect of adrenaline?
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Exercise?
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5c Running repairs
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Heart Conditions/Diseases
Condition
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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
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Blood components
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Blood groups: A, B, AB, O
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Rhesus positive & negative
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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
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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
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Simple organisms e.g. amoeba through skin
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Complex organisms through specialist organs
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Fish gills
Respiratory System
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5d Breath of life
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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
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Measuring Breathing
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Tidal air/volume – volume of air in a normal breath
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Vital capacity – maximum volume breathed in & out
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Residual air/volume – air
that remains in lungs
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Respiratory Diseases
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Industrial e.g. asbestosis
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Genetic e.g. cystic fibrosis
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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
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Excretion – getting rid of waste e.g. CO2, urea, sweat
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Defecation – getting rid of solid waste through the anus
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Excretory organs: lungs, kidneys, liver, skin
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Skin structure:
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Excess water & salt are
excreted as sweat, which
evaporates
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5e Waste Disposal
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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
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Made in pituitary gland
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Negative feedback:
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Water content low -> ADH released -> nephron tubules more
permeable -> normal water level
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Dialysis Machine
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Waste diffuses from blood into
dialysis fluid
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Sodium & glucose in blood
replaced
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5f Life goes on
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Fertilisation – fusion of a male & female gamete
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Reproductive systems:
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5f Life goes on
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Menstrual Cycle
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Day 1-5 – menstruation
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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
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Fertility drugs – FSH injected to stimulate egg release
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Artificial insemination
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Egg donation – problem? Only has genes from one parent
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Ovary transplant
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Surrogacy – problem? Emotional attachment
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IVF – problem? low success rate, twins/triplets more likely
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Foetal Screening – for health of baby
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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
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Organ Donation
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Biological replacement e.g. blood, cornea, heart, lungs,
kidney & bone marrow
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Organs must be: healthy, right size & age, tissue matched
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Can be from living donors e.g. kidneys or dead donors if
they cannot regain consciousness & breath unaided
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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
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Growth – animals grow in the early stages of life, plants grow
continually in areas called meristems e.g. shoot tips
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New cells for growth made by mitosis
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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