Chapter 33 - The Nervous System

Question 1

Central nervous system (CNS)

Answer 1

Brain and spinal cord

Question 2

Peripheral nervous system (PNS)

Answer 2

Vast network of nerves - carry messages between body and CNS

Question 3

Neuron

Answer 3

Nerve cell

Question 4

Sensory neuron (afferent)

Answer 4

Takes a message from a sense organ to CNS

Question 5

Motor neuron (efferent)

Answer 5

Takes a message from the CNS to a muscle gland

Question 6

Ganglion

Answer 6

A group of cell bodies located outside the CNS

Question 7

Interneuron

Answer 7

Carries information between sensory and motor neurons

Question 8

Threshold

Answer 8

The minimum stimulus needed to cause an impulse to be carried in a neuron

Question 9

The ‘all or nothing’ law

Answer 9

If the threshold is reached an impulse carried, but if the threshold is not reached no impulse is carried

Question 10

Refractory period

Answer 10

A short time span after a neuron has carried an impulse during which a stimulus fails to cause a response

Question 11

Synapse

Answer 11

A region where two neurons come into close contact

Question 12

Synaptic cleft

Answer 12

The tiny gap between the two neurons at a synapse

Question 13

Reflex action

Answer 13

An automatic, involuntary, unthinking response to a stimulus

Question 14

Reflex arc

Answer 14

The pathway taken by a nerve impulse in a reflex action