A muscle spindle responds to the ____.
A) oxygen level in the muscle
B) acetylcholine concentration at the nerve-muscle junction
C) fatigue of the muscle
D) stretch of the muscle

Question

Quizplus · Accepted Answer

A muscle spindle responds to the stretch of the muscle. These structures are sensory receptors located within the muscle fibers that detect changes in muscle length and play a role in reflexive muscle movements. When a muscle is stretched, the muscle spindle sends signals to the spinal cord which activates motor neurons to contract the muscle and prevent overstretching.

A Muscle Spindle Responds to the ____