Chapter 14 - The Central Nervous System

Question 1

What is the collective name given to the brain and spinal cord?

Answer 1

The central nervous system.

Question 2

Name the 5 main organs involved in detecting conditions inside and outside the body.

Answer 2

• Ears
• Eyes
• Nose
• Mouth
• Skin

Question 3

What term is used to mean something a sense organ responds to.

Answer 3

Stimulus.

Question 4

Within a sense organ, specific cells called receptors detect a stimulus. How do they react when stimulated?

Answer 4

They create impulses which usually travel to the brain.

Question 5

What type of cell carries a signal from a receptor to the CNS?

Answer 5

Sensory neurone

Question 6

How does a signal move through a sensory neurone?

Answer 6

Electrical impulse

Question 7

What is the purpose of the myelin sheath?

Answer 7

Insulation and speeding up the impulse

Question 8

How would the function of a sensory neurone be different without myelin?

Answer 8

It would lose energy through lack of insulation, and the transportation of electrical impulses would be slower as there would be no impulse jump.

Question 9

What is the most obvious way to distinguish a sensory neurone from a motor neurone?

Answer 9

The location of the cell body.

Question 10

Give two similarities between the structures of a motor and a sensory neurone.

Answer 10

1. Both have dendrites

2. Both have cell bodies

Question 11

Give two differences between the structures of a motor and a sensory neurone.

Answer 11

1. Sensory neurones have a longer dendron; motor neurones have a longer axon.
2. In a motor neurone, the cell body is located within the dendrite structure.

Question 12

What is the function of a motor neurone?

Answer 12

They carry impulses to effectors.

Question 13

What would be connected to the axon terminals of a sensory neurone?

Answer 13

A relay neurone

Question 14

What would be connected to the axon terminals of a relay neurone?

Answer 14

A motor neurone

Question 15

What would be connected to the axon terminals of a motor neurone?

Answer 15

Muscle cells

Question 16

How does an electrical impulse cross a synapse?

Answer 16

Neurotransmission.

Question 17

Explain the process of neurotransmission.

Answer 17

Vesicles in the axon terminals are triggered by an electrical impulse to eject neurotransmitters into the synapse. The receptors of the corresponding dendrites detect the neurotransmitters and a new electrical impulse is triggered.

Question 18

Give 2 reasons why synapses are useful for the nervous system.

Answer 18

1. Neurotransmitters are only released from axon terminals, so impulses only flow in one direction.
2. They allow many fresh impulses to be generated in many neurones.

Question 19

What is a voluntary response?

Answer 19

A conscious action.

Question 20

What is a reflex response?

Answer 20

Responses that protect us from danger but don’t involve the brain.

Question 21

Which direction does an afferent signal travel?

Answer 21

In through the sensory neurone.

Question 22

Which direction does an efferent signal travel?

Answer 22

Out through a motor neurone.