The Nervous System

Question 1

Stimulus

Answer 1

Change in the environment that causes a response

Question 2

Receptor

Answer 2

A cell sensitive to a stimulus (eg pain receptor)

Question 3

Effector

Answer 3

Cell that responds to a stimulus (eg muscle moves)

Question 4

Dendron

Answer 4

Carries impulse towards cell body

Question 5

Axons

Answer 5

Carries impulses away from cell body’s

Question 6

Schwann cells

Answer 6

Makes the myelin sheath

Question 7

Myelin sheath

Answer 7

Fatty membrane wrapped around an axon or dendron which speeds up an electrical impulse

Question 8

Nodes of ranvier

Answer 8

Gaps in myelin sheath that speed up impulse transmission

Question 9

Ganglion

Answer 9

Group of cell bodies located outside the CNS

Question 10

Threshold

Answer 10

Minimum stimulus needed to generate an electrical impulse

Question 11

‘All or nothing’ law

Answer 11

If threshold is not reached, no impulse is sent

Question 12

Synapses

Answer 12

Region where two neurone come into close contact but do not touch

Question 13

Synaptic cleft

Answer 13

The gap between two neurons

Question 14

Reflex action

Answer 14

And automatic in voluntary unconscious response to a stimulus

Question 15

Neuron

Answer 15

A nerve cell