Monosynaptic reflex

A monosynaptic reflex is a quick, automatic response where a muscle contracts in reaction to a stretch. When a muscle is stretched, sensory nerve fibers send signals directly to the spinal cord, where they connect to motor neurons through a single synapse. These motor neurons then send a signal back to the same muscle, causing it to contract and counter the stretch. This simple and fast reflex helps maintain posture and muscle balance without needing brain involvement. An example is the knee-jerk reflex tested with a hammer, which occurs through this monosynaptic pathway.