5.2 Nervous system (Combined)

Question 1

What is the function of the nervous system?

Answer 1

The nervous system allows the body to react to its surroundings and coordinate an appropriate response

Question 2

How does a stimulus lead to a response being carried out in the body?

Answer 2

1. Stimulus is converted into an electrical impulse by the receptors
2. The electrical impulse passes along sensory neurones to the central nervous system
3. The central nervous system coordinates an appropriate response and an electrical impulse is sent along motor neurones to the effector, which carries out a response

Question 3

What sequence of events describes how the nervous system works?

Answer 3

Stimulus → Receptor → Coordinator → Effector → Response

Question 4

What is a reflex action?

Answer 4

A reflex action is an automatic and rapid response which does not involve any conscious input from the brain

Question 5

Why are reflex actions important?

Answer 5

Reflex actions aid survival by preventing harm to the body

Question 6

Describe how a reflex action occurs via a reflex arc

Answer 6

1. The stimulus is detected by a receptor
2. An electrical impulse passes along a sensory neurone to the spinal cord (part of the CNS)
3. At a synapse, between a sensory neurone and a relay neurone, a chemical diffuses across the gap and stimulates a new impulse which passes along the relay neurone
4. The same process occurs at a synapse between a relay neurone and a motor neurone
5. At the effector, an appropriate response is carried out

Question 7

What is the difference between a reflex pathway and a conscious pathway?

Answer 7

Within a reflex pathway, the coordination centre is a relay neurone found in the spinal cord/unconscious parts of the brain.

In a conscious pathway, the coordination pathway is in a conscious part of the brain.