Science glossary film: Reflex arc

A neural pathway involved in a reflex response. For example, when your knee is tapped below the kneecap, causing the leg to jerk upwards. At its simplest a reflex arc can consist of just three neurons: one that reacts to the stimulus, which connects via another in the spinal cord, to a motor neuron that tells a muscle to react. Bypassing the brain in this way produces a quicker reaction.

For example, when your knee is tapped below the kneecap, causing the leg to jerk upwards. At its simplest a reflex arc can consist of just three neurons: one that reacts to the stimulus, which connects via another in the spinal cord, to a motor neuron that tells a muscle to react. Bypassing the brain in this way produces a quicker reaction.