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Reflex actions





Reflex action: a way for the body to automatically and rapidly respond ...

... to a stimulus to minimise any further damage to the body.

It follows this general sequence and doesn't involve the brain:

stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector → response [1]





Reflex arc

Reflex arc: the nerve pathway followed by a reflex action.

For example, a simple reflex arc happens if we accidentally touch something hot. [2]

Process of reflex arc

1. Receptor in the skin detects a stimulus (the change in temperature).

2. Sensory neurone sends impulses to relay neurone.

3. Motor neurone sends impulses to effector.

4. Effector produces a response (muscle contracts to move hand away). [3]

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