B3.1.1 Nervous System

Question 1

How does the nervous system work?

Answer 1

Detects changes in external environment, info sent to brain, brain decides on appropriate response, sends impulse to body part, body part responds

Question 2

main stages to nervous response

Answer 2

Stimulus-change in environment
Sensory Receptors-group of cells which detect stimulus
Effectors-muscles which respond to an impulse by contracting, causing movement OR glands which respond by releasing hormones

Question 3

Where are receptor cells found?

Answer 3

Sense organs and detect different stimuli

Eg. In eye, light receptor cells detect changes in light

Question 4

What do receptor cells do?

Answer 4

Change the stimulus into electrical impulses that travel along neurones to CNS

Question 5

What is the CNS?

Answer 5

Central Nervous System

=brain and spinal cord

Question 6

What do sensory neurones do?

Answer 6

Carry electrical impulses from receptor cells to the CNS

Question 7

What do relay neurones do?

Answer 7

Carry electrical impulses from sensory neurones to motor neurones

Question 8

What do motor neurones do?

Answer 8

Carry electrical impulses from the CNS to effectors

Question 9

What are nerves?

Answer 9

Bundles of hundreds and thousands of neurones

Question 10

Flow diagram for steps in nervous reaction

Answer 10

Stimulus —> receptor cells —> sensory neurone —> spinal cord
—>brain —> spinal cord —> motor neurone —> effector —>
response
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