The Nervous System and Reflexes

The Nervous System and Reflexes

The nervous system lets the body detect and respond to changes rapidly, using electrical signals sent along neurons (nerve cells).

The reflex arc

A reflex is an automatic, rapid response that doesn't involve conscious thought — a stimulus (like touching something hot) is detected by a receptor, sent along a sensory neuron to the spinal cord, where it passes through a relay neuron directly to a motor neuron, which triggers a muscle response — bypassing the brain for speed.

Why reflexes matter

Reflexes protect the body from harm faster than a conscious decision could — by the time you'd consciously registered the pain, a reflex has already pulled your hand away.

Practice

Why does a reflex not involve the brain making the decision?