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Biology Revision

B5 The Living Body

+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

+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

+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?

+5a In good shape The arm

Biceps & triceps are antagonistic muscles

Arm is like a lever:

Biceps contract, triceps relax -> arm raises

+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

+5b The vital pump Cardiac Cycle – controlled by SAN & AVN

ECG

Effect of adrenaline?

Exercise?

+5c Running repairs Heart Conditions/Diseases

Lifestyle risk factors– diet, alcohol smoking, stress, drugs

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?

+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

+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

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

+5d Breath of life Gas Exchange

Simple organisms e.g. amoeba through skin

Complex organisms through specialist organs

Fish gills Respiratory System

+5d Breath of life Breathing

Volume of chest cavity increases, pressure in lungs falls

Volume in chest cavity decreases, pressure in lungs rises

+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

Pathogenic e.g. pneumonia

Asthma – irritated bronchioles narrow, muscles tighten, more mucus produced

+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

+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

+5e Waste Disposal 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

Dialysis Machine

Waste diffuses from blood into

dialysis fluid

Sodium & glucose in blood

replaced

+5f Life goes on Fertilisation – fusion of a male & female gamete

Reproductive systems:

+5f Life goes on

Menstrual Cycle

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/corpus luteum

Preserve uterus lining

+5f Life goes on Infertility

Fertility drugs – FSH injected to stimulate egg release

Artificial insemination

Egg donation – problem? Only has genes from one parent

Ovary transplant

Surrogacy – problem? Emotional attachment

IVF – problem? low success rate, twins/triplets more likely

Foetal Screening – for health of baby

Ultrasound

Anmiocentesis – tests cells from amniotic fluid using hypodermic needle, Ethical issues? Can cause miscarriage (1 in 200), termination?

+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

mechanicalProblems with Biological

Size Shortage of donors

Power supply Tissue match/ immunosuppresants

Material used (non wearing)

Rejection

Body reactions e.g. allergic

+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)

Problems of living longer?

Growth is measured as gain in height & mass

Determined by:GenesDietExerciseHormonesHealth/disease

Human growth hormone – made in pituitary gland – releases energy for growth from fat stores, stimulates growth of long bones