Flashcards · Biology · The Nervous System
Sensory Receptors and Neurones
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What is a stimulus?
A change in the environment that can be detected by a receptor.
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What does a sensory receptor do?
It detects a stimulus and converts it into an electrical impulse.
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Which two organs make up the central nervous system?
The brain and the spinal cord.
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Name the two types of effector.
Muscles and glands.
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What does a muscle do when it receives an impulse?
It contracts.
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What does a gland do when it receives an impulse?
It secretes a substance, such as a hormone.
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Which type of neurone carries impulses to the CNS?
Sensory neurones.
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Which type of neurone carries impulses away from the CNS?
Motor neurones.
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Where are relay neurones found?
Inside the central nervous system, in the brain or spinal cord.
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What is the job of a relay neurone?
To pass impulses from sensory neurones to motor neurones.
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What is the function of the myelin sheath?
It insulates the neurone and makes the impulse travel faster.
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What is the dendron of a sensory neurone?
A long extension that carries the impulse towards the cell body.
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What is the axon of a neurone?
The extension that carries the impulse away from the cell body.
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Why do neurones have branched ends?
To connect with many other neurones and share information.
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Which type of receptor is found in the retina?
Light receptors (rod and cone cells).
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What happens to impulses when myelin is damaged?
They travel more slowly or are lost, as in multiple sclerosis.
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Why is a neurone called a specialised cell?
It has a long, insulated, branched structure that suits it to carrying electrical impulses.
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A pain receptor in the skin is triggered by a pin. Which neurone carries the impulse next?
A sensory neurone.