The Nervous System

Question 1

Describe the structure and function of the nervous system.

Answer 1

• It consists of two parts: the central nervous system, which is the brain and the spinal cord, and other nerves running to and from it
• It allows all parts of the body to communicate

Question 2

The body has lots of sensory receptors.

What are receptors?

Answer 2

Receptors are groups of cells in sense organs that can detect stimuli

Question 3

The nervous system is made up of neurones.

What are neurones?

Answer 3

• Nerve cells which go to all parts of the body
• They transmit information rapidly as electrical impulses

Question 4

Describe one feature every neurone has.

Answer 4

All neurones have a cell body with a nucleus

Question 5

A cell body has extensions that connect to other neurones.

Give examples of these.

Answer 5

• Dendrons / dendrites
• Axons

Question 6

Describe the function of dendrites / dendrons.

Answer 6

Dendrites / dendrons carry impulses towards the cell body

Question 7

Describe the function of axons.

Answer 7

Axons carry impulses away from the cell body

Question 8

List three types of neurones.

Answer 8

• Sensory neurone
• Relay neurone
• Motor neurone

Question 9

Describe the structure and function of a sensory neurone.

Answer 9

• Has one long dendron and one short axon
• Carries impulses from receptor cells to the central nervous system

Question 10

Describe the structure and function of a relay neurone.

Answer 10

• Has many short dendrites surrounding the cell body and an axon leading away from it
• Carries impulses around the central nervous system to motor neurones

Question 11

Describe the structure and function of a motor neurone.

Answer 11

• Has many short dendrites and one long axon
• Carries impulses from the central nervous system to effector cells

Question 12

Some neurones are surrounded by a myelin sheath.

Describe the role of the myelin sheath.

Answer 12

It insulates the neurone, speeding up electrical impulses

Question 13

Describe the pathway of an impulse through the nervous system.

Answer 13

• When stimuli is detected by receptors, the information is converted to an electrical impulse
• This is sent along sensory neurones to the central nervous system
• An impulse travels through the CNS along relay neurones, and the CNS coordinates a response
• The impulse is sent along a motor neurone from the CNS to an effector
• The effector then responds, (e.g. a muscle may contract or a gland may secrete a hormone)