Reflex Arc - GCSE Biology Definition

A reflex arc is the pathway taken by nerve impulses during a reflex action. It allows the body to respond quickly to a stimulus without involving the conscious part of the brain. The reflex arc begins when receptors detect a stimulus, such as heat or pain. This information travels along a sensory neurone to the spinal cord. There, it passes through a relay neurone and is then sent along a motor neurone to an effector, usually a muscle, which carries out the response (e.g. pulling your hand away). Reflex arcs are important because they produce fast, automatic actions that help protect the body from harm.