Topic 2 - Responding To Change: Investigating Stimuli And Reflexes

Question 1

What is an effector and what does it do?

Answer 1

Effectors can be muscles or glands. They respond to signals from the central nervous system that come via motor neurones. Muscles contract in response and glands secrete hormones.

Question 2

Explain why reflex responses happen so quickly.

Answer 2

Reflexes pass through an unconscious part of the brain or just the spinal cord so you don’t think about them, which makes them quicker.

Question 3

What happens in a reflex arc?

Answer 3

A stimulus is detected by receptors and impulses are sent along a sensory neurone to the central nervous system. The impulse is then sent along a relay neurone and then to a motor neurone. From the motor neurone, the impulse goes to an effector. The effector responds by contracting if it’s a muscle or by releasing hormones if it’s a gland.