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Keywords for B4

21st Century

Science OCR

Homeostasis

Keeping

a steady state inside your body

Receptor

The

part of the control system that detects changes in the system and passes this

information to the processing centre

Processing Centre

The

part of the control system that receives and processes information from the

receptor, and triggers actions by the effectors

Effectors

The

part of the control system that brings about the change to the system

Antagonistic Effectors

Antagonistic

effectors have opposite effects

Enzymes

A

protein that catalyses (speeds up) chemical reactions in living things

Active Site

The

part of an enzyme where the reacting molecules fit into

Denatured

An

enzyme is said to be denatured when it cannot change back, like cooked egg

whites

Optimum Temperature

The

temperature at which enzymes work fastest

Respiration

A

series of reactions in cells which release energy for the cell to use

Extremities

Parts

of the body away from the core, for example fingers and toes

Core

(Of

the body) central parts of the body where the body temperature is kept constant

Hypothamolus

The

part of the brain that controls many different functions, for example body

temperature

Shivering

Very

quick muscle contractions. Releases more energy from muscle cells to raise body

temperature

Vasoconstriction

Narrowing

of blood vessels

Vasodilatation

Widening

of blood vessels

Partially Permeable Membrane

A

membrane that acts as a barrier to some molecules, but allows others to diffuse

freely

Osmosis

The

diffusion of water across a partially permeable membrane

Active Transport

Active

Transport is where molecules are moved in or out of a cell using energy. This

process is used when transport needs to be faster than diffusion, and when

molecules are being moved from a region where they are at low concentration to

where they are at high concentration

Kidneys

Organs

in the body which remove waste urea from the blood, and balance water and salt

levels

Excretion

The

removal of waste products of chemical reactions from cells

Urea

A

waste product made by the liver from the breaking down of amino acids the body

does not use

Urine

Waste

excreted from the body in the kidneys and stored in the bladder

Ecstasy

Ecstasy

is a recreational drug that increases the concentration of serotonin at the

synapses in the brain giving pleasurable feelings. Long term use may cause

damage to the synapses

ADH

It

is a hormone making kidney tubules more permeable to water, causing greater re-absorption

of water.

Pituitary Gland

Part

of the human brain which coordinates many different functions, for example the

release of ADH

Heat Stroke

A

life threatening rise in body temperature where the body temperature control

system fails

Hypothermia

A

fall in body temperature to below 350C

Adolescence- 11-15 years of age

Afferent arteriole- Blood vessel that carries blood into the glomerulus

Agglutinins- Antigens (proteins) on the surface of red blood cells that determine

your blood group

Amniocentesis- Test that may be carried out on pregnant women to test for foetal

abnormality (problems with the foetus)

Atria-

Top chambers of the heart that receive blood from veins

AVN-

Atrioventricular node, part of the pacemaker in the heart that transmits

electrical impulses to the central part of the heart

Blood vessels- Tube-like structures that carry blood throughout the body. Blood

vessels include arteries, veins and capillaries

Bone-

Living tissue that makes up most of the skeleton; bone is rigid

Breathing-

Movements of the rib cage a diaphragm that cause air to enter and leave the

lungs

Bypass surgery- Operation in which a piece of blood vessel is taken from elsewhere in

the body and transplanted to bypass blocked coronary arteries, supplying the

heart muscles with blood

Carbohydrase- Enzyme that digests carbohydrates to simple sugars

Cartilage-

Living tissue that occurs in the skeleton; cartilage is tough and elastic

Childhood-

2-11 years of age

Conception- Formation of a fertilised egg; the start of pregnancy

Constrict-

Get narrower

Contraception- Preventing pregnancy (preventing pregnancy)

Donor-

Someone who donates (gives) something, such as an organ in an organ transplant

ECG-

Electrocardiogram, a trace measured by doctors that shows the electrical

activity in the heart

Efferent arteriole- Blood vessel that carries blood away from the glomerulus

Fibrin-

Insoluble protein that forms a blood clot when you cut yourself

Genitals-

Primary sexual characteristics- The external features that show the sex of an

individual

Glomerulus- Knot of capillaries in the nephron of the kidney, where filtration

occurs

Gullet-

Another name for oesophagus; in the digestive system, a tube that leads from

the mouth to the stomach

Heart-

Muscular organ that pumps blood around the body

Immunosuppressant drugs- Drugs that suppress the immune system, given to recipients of a

transplanted organ to reduce the risk of rejection

Infancy-

First 2 years of life

IVF-

In vitro fertilisation- method to help achieve pregnancy in women who cannot

become pregnant naturally

Large intestine- Part of the digestive system where water and some minerals are absorbed

into the blood

Life expectancy- Number of years people might normally be expected to live

Ligament-

Tissue that holds bones together at a joint

Lipase-

Enzyme that digests fats to fatty acids and glycerol

Lung capacity- Total volume of the lungs, made up of vital capacity plus residual air

Macrophage- White blood cell that ingests foreign particles and pathogens

Maturity-

Having reached full adult at around 18-20 for males and 16 years for females

Miscarriage- Early ending of pregnancy, when the foetus dies

Mouth-

First part of the digestive system, where food enters; contains salivary glands

Oesophagus- Another name for gullet; in the digestive system, a tube that leads

from the mouth to the stomach

Old age-

Over about 60-65 years of age

Ovulation-

Release of a mature egg from an ovary

Permeable-

Allows substances to pass through it freely

Pituitary gland- Gland in the brain that secretes hormones, including antidiuretic

hormone (ADH)

Platelets-

Small structures in the blood that are involved in blood clotting

Protease-

Enzyme that digests proteins to fatty amino acids

Pulse-

Expansions and recoil of the arteries as blood is pumped into them from the

heart. The pulse gives a measure of the heart rate

Rejection-

Attack on a transplanted organ by the immune system within a recipient’s body

Residual air- Air that remains in the lungs after you have breathed out fully

Respiration- Process by which living things release energy from carbohydrates, also

producing water and carbohydrates

SAN-

Sinoatrial node, part of the pacemaker in the heart that produces electrical

impulses which cause the atria to contract

Selective reabsorption- Absorption of useful substances such as glucose from the kidney tubule

back into the blood

Sex hormones- Hormones that control sexual features; oestrogen and progesterone in

females, and testosterone in males

Small intestine- Part of the digestive system where chemical digestion is completed and

absorption occurs

Stomach-

Part of the digestive system where physical and chemical digestion occur

Synovial joint- Joint in the body what is lubricated by synovial fluid, such as the

knee, hip and elbow. The joint also has a synovial membrane, ligaments and

cartilage

Tendon-

Tissue that connects muscles to bones; tendons are tough and do not stretch

Tidal volume- Volume of air breathed in during one breath

Tissue match- Matching the tissues of donor and recipient in a transplant operation,

so that their antigens are similar and there is less chance of rejection

Traumatic-

Physically damaging

Urea-

Substance produced in the liver from the breakdown of amino acids and removed

by the kidneys in the urine

Ventilation- Movement of air into and out of the lungs, brought about by inhaling

and exhaling

Ventricles- Lower chambers of the heart that contract and force blood out of the

heart into the arteries

Vital capacity-

Maximum volume of air you can breathe in, plus your tidal volume, plus the

maximum volume of air you can breathe out after taking a big breath in

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