Stretch reflex

Rather, muscle spindles detect a stretch and convey the information to the central nervous system.

This increases alpha motor neuron activity, causing the muscle fibers to contract and thus resist the stretching.

Gamma motoneurons regulate how sensitive the stretch reflex is by tightening or relaxing the fibers within the spindle.

The efferent motor neuron is the structure that carries the signal from the spinal cord back to the muscle.

It carries the action potential from the ventral root of the spinal cord to the muscle down the alpha motor neuron.

The postural muscles that are closely connected to the vertebral column on the opposite side will stretch.

The responses from these pathways are often termed medium or long latency stretch reflexes, because the time course is longer due to distance it needs to travel.

Reflexes can be tested as part of a neurological examination, often if there is an injury to the central nervous system.

[8] The clasp-knife response is a stretch reflex with a rapid decrease in resistance when attempting to flex a joint.