stretch receptor
Quick Summary
A stretch receptor, also known as a muscle spindle, is a sensory receptor found within muscles. These receptors are crucial proprioceptors, providing the central nervous system with information about the body's position and movement.12
Muscle spindles are composed of specialized muscle fibers surrounded by a connective tissue sheath. They are arranged parallel to the main muscle fibers and contain a non-contractile sensory midsection that detects changes in muscle length and tension. When a muscle is stretched, the midsection of the muscle spindle is elongated, increasing nerve impulse frequency. This activity elicits a reflex contraction of the stretched muscle, helping to maintain posture and coordinate movements.2
Tendon organs, located in tendons, are another type of stretch receptor, though less sensitive than muscle spindles. They respond to stretch by causing relaxation of the attached muscle, which can help prevent damage. Together, muscle spindles and tendon organs provide essential feedback for movement control and body awareness.34
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