Biology Homeostasis revsion

What is contained in the central nervous system (CNS)?
The brain and spinal cord
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Homeostasis definition
The regulation of internal conditions in a cell or organism in response to internal and external changes
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What are the main three internal conditions which need to be regulated?
Body glucose, water, body temperature
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What are sensory neurons?
Neurones that carry information as electrical impulses from the receptors to the CNS
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What are motor neurones?
Neurones which carry electrical impulses from the CNS to effectors
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What is an effector?
All muscles and glands, which respond to nervous impulses
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Receptor definition
Cells that detect stimuli
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Synapse defintion
Connection between two neurones
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What does the cerebral Quartex control in the brain?
Consciousness, intelligence, memory, language
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What does the medulla control in the brain?
Unconscious activity (e.g. Breathing, Heart Beat)
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What does the cerebellum control in the brain?
Muscle coordination
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Name the 3 mains ways scientists study the brain
Studying patients with brain damage, electrically stimulating the brain, MRI scans
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Sclera definition
Tough, supporting wall of the eye
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Cornea definition
Transparent outer layer at the front of the eye, refracts light into the eye
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Iris definition
Controls diameter of pupil and how much light goes into the eye
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Lens definition
Focuses light onto retina
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Retina definition
Contains receptor cells sensitive to light intensity and colour
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What is the shape of the eye controlled by?
Ciliary muscles and suspensory ligaments
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Optic Nerve definition
Carries impulses from the receptor on the retina to the brain
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What happens when light is bright?
Pupil grows smaller, circular muscles contract and radial muscles relax
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What happens when light is dark?
Pupil grows bigger, circular muscles relax and radial muscles contract
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Why are people long-sighted?
The lens doesn't refract enough light, or eyeball is too short
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Why are people Short-sighted?
Lenin refracts light too much, or eyeball is too long
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Which glasses are used for long/short sighted people?
Long - convex lens Short - Concave Lens
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Name 3 treatments for vision defects (long/short sightedness)
Contact lenses, Laser Eye Surgery, replacement lens surgery
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How does your body react to being too hot?
Sweat (transfers thermal energy to environment), Vasodilation (blood vessels dilate so blood flows close to the skin)
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Vasodilation defintion
When blood vessels dilate so blood flows closer to the skin, cooling you down
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How does your body react to being to cold?
Hairs stand up (traps insulating layer of air), vasoconstriction (blood vessels constrict to close off the skins' blood supply), shivering
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Vasoconstriction definition
Blood vessels supplying the skins' blood supply constrict to close off the supply
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Accommodation definition
Process of changing the shape of the lens to focus on near or far objects
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What in the brain controls regulation of body temperature?
The thermoregulatory centre
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What is the optimum temperature for the body?
37°c
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Why does body temperature have to be maintained?
Enzymes need to work at their optimum temperature
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Hormones definition
Chemical molecules released directly into the blood
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Where is testosterone produced?
The Testes (only men)
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Where is oestrogen produced?
The ovaries
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Target organs defintion
The target cells in organs which
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Where is thyroxine produced?
The thyroid
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Where is insulin produced?
The Pancreas
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Where is adrenaline produced?
The adrenal gland
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What is the purpose of thyroxine?
Regulating rate of metabolism, heart rate and temperature
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What is regulated be insulin?
Blood glucose levels
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Diabetes definition
A condition that affects your ability to control blood glucose levels/ produce insulin
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Puberty definition
A period where secondary sex characteristics are developed
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Filtration definition
The process of waste products being filtered out of the blood through the kidneys
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Selective reabsorbtion definition
When some useful substances (e.g. Glucose, some Ions, Water) are reabsorbed back into the blood
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Which hormone controls concentration of urine?
Anti-diuretic hormone (ADH)
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The menstrual Cycle definition
The monthly release of an egg from a woman's ovaries
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What are the 4 hormones that control the menstrual cycle?
FSH, LH, progesterone, oestrogen
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Which hormones in the menstrual cycle are produced by the pituitary gland?
FSH, LH
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Which hormones in the menstrual cycle are produced in the ovaries?
Oestrogen and Progesterone
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What does LH do?
Stimulates the release of an egg at day 14
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What does FSH do?
Causes an egg to mature in one of the ovaries, stimulates the ovaries to produce progesterone
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What does oestrogen do?
Causes the lining of the uterus to grow, inhibits the release of FSH and LH
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What does adrenaline do?
Causes an increase of oxygen and glucose to the cells in the brain
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What does auxin do in a plant?
Controls a plants growth in response to light and gravity
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Other cards in this set

Card 2

Front

Homeostasis definition

Back

The regulation of internal conditions in a cell or organism in response to internal and external changes

Card 3

Front

What are the main three internal conditions which need to be regulated?

Back

Preview of the front of card 3

Card 4

Front

What are sensory neurons?

Back

Preview of the front of card 4

Card 5

Front

What are motor neurones?

Back

Preview of the front of card 5
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