Which muscle receptors are involved in the body's stretch reflex?

The body's stretch reflex is primarily governed by two types of muscle receptors: muscle spindles and Golgi tendon organs.

Muscle spindles play a crucial role in detecting changes in muscle length and the rate of that change, which is essential for triggering the stretch reflex. When a muscle is stretched, the muscle spindles send signals to the central nervous system indicating this change, which leads to an appropriate response to contract the muscle. This reaction helps maintain posture and balance during movement.

Golgi tendon organs, on the other hand, are located at the junction between muscles and tendons. They respond to changes in muscle tension rather than length. These receptors provide feedback regarding the force exerted by muscles and protect muscles from excessive tension that could lead to injury.

Understanding that both receptor types contribute to the body's motor control system helps clarify why the correct choice includes both. While muscle spindles directly mediate the stretch reflex, Golgi tendon organs assist in regulating muscle tension and preventing overload, creating a comprehensive feedback mechanism that supports muscle function and injury prevention.