2.2 Reflex Actions

Question 1

Explain the process of a reflex action

Answer 1

1. A receptor detects a stimulus, ex sharp pain
2. A sensory neurones transmits the impulse to the CNS (spinal cord, not brain)
3. Relay neurone passes the impulse on
4. A motor neurone is stimulated
5. The impulse passes to an effector
6. Action is taken

Question 2

What is a synapse?

Answer 2

The junction between two neurones

Question 3

How are the electrical impulses transmitted across the synapse?

Answer 3

They are transmitted by chemicals

Question 4

Why isn’t the brain used in a reflex arc?

Answer 4

It takes more time for the impulses to reach the brain whilst our bodies are in danger so the part of the CNS used is the spinal cord

Question 5

What is the function of a relay neurone?

Answer 5

The relay neurone is located in the spinal cord in the CNS used in reflex arcs to transmit the electrical impulses through the spinal cord

Question 6

What are reflex actions?

Answer 6

Rapid, automatic responses to a stimulus to protect us from damage