B5 Homeostasis and response

Question 1

Describe the role of the human nervous system.

Answer 1

The human nervous system enables humans to react to their surroundings and to coordinate their behaviour.

Question 2

What is the central nervous system?

Answer 2

The central nervous system comprises of:

• the brain
• the spinal cord

Question 3

How is information from receptors passed through the nervous system?

Answer 3

The information is passed through the nervous system as electrical impulses.

Question 4

Describe the pathway through the nervous system, starting at the receptor.

Answer 4

The pathway is as follows:

stimulus –> Receptor –> Coordinator –> Effector –> Response

Question 5

What is the role of receptors?

Answer 5

Receptors detect a change in the environment.

Question 6

What is the role of an effector?

Answer 6

An effector brings about a response. Effectors can be muscles (eg hand muscles contracting to move a hand away from a hot plate) or glands secreting hormones (eg the pancreas releasing insulin)

Question 7

What is the role of a sensory neurone?

Answer 7

A sensory neurone carries signals from the receptors to the spinal cord or brain.

Question 8

What is the role of a relay neurone?

Answer 8

A relay neurone carries messages from one part of the CNS to another

Question 9

What is the role of a motor neurone?

Answer 9

Motor neurones carry signals from the CNS to effectors.

Question 10

What is a reflex action?

Answer 10

A reflex action is automatic and rapid. It does not involve the conscious part of the brain.

Question 11

How are electrical impulses carried between neurones?

Answer 11

Between neurones are junctions called synapses. electrical impulses are converted in to chemical signals as neurotransmitter. The neurotransmitter diffuses across the synapse where it is the converted back in to an electrical impulse.