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What is homeostasis
the regulation of the internal conditions of a cell/organism to maintain optimum conditions for function in response to internal and external changes.
What are the 3 things all control systems include ?
Receptors(detect a stimulus)
Coordination centre (CNS/pancreas)
Effector (muscle/glands)
Label the diagram
A- Dendron
B- nucleus
C- axon
D- nerve endings
E- cytoplasm
F- cell membrane
How has the structure of the nervous system adapted to its function ?
Long axon so can carry messages up and down the body over long distances.
Fill in the gaps
describe the image and label the colours
Receptors detect a stimulus
Red- sensory neurone, send electric impulses to relay neurone in the CNS.
Green- relay neurone, Connect sensory neurones to motor neurones.
Blue- motor neurone, send electric impulses to effector
Effector produces a response (hand contracts away from flame)
What is a synapse ?
a gap between 2 nerve cells
that allows neurotransmitters to diffuse across into the next nerve cell.
What is a reflect act and why is it important?
Automatic and rapid, do not involve conscious part of brain.
They protect your body from harm
Label diagram and functions of each section.
Pink- cerebral cortex - (consciousness, intelligence, memory and language)
Green - cerebellum - (muscle coordination/balance)
Lilac - medulla - (unconscious activities/breathing/heartbeat)
Yellow - hypothalamus (regulating body temperature)
3 methods of studying the brain
electrically stimulate different parts of the brain
Studying patients with brain damage
Brain scan (PET, CT), (MRI - different parts of the brain light up)
3 main reasons treating the brain is difficult
it’s incased within the skull, so is hard to access
It is very complicated, so hard to target with medications
Mental illness/ infection
What happens when the body temperature is too high?
Blood vessels dilate, (vasodilation)
sweat is produced from the sweat glands
transfers energy from the skin to the environment
What happens if the body temperature is too low?
Blood vessels constrict (vasoconstriction)
sweat stops and skeletal muscles contract (shiver)
This needs respiration which transfers some energy to warm the body.
What are hormones ?
Chemical molecules release directly into the blood
What are myelin sheaths ?
Insulation sheath that around nerves
Made of protein and fatty substances
Allow electrical impulses to transmitt
describe how glasses and contact lenses can correct short-sightedness.
concave lenses (thinner in middle)
Light rays bend/refracted outward
Light rays focused on retina
Explain why a short sighted person has difficulty seeing distant objects nearby
eyeball too long/ lens cannot be thin enough/ ciliary muscles are too weak
So light focuses in front of the retina
Which structure do light rays focus on ?
Retina
definition of myopia
Short-sightedness
Definition of hyperopia
Long-sightedness
Note 
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