Which sensor detects changes in length and rate of stretching, triggering a protective contraction if overstretched?

Which sensor detects changes in length and rate of stretching, triggering a protective contraction if overstretched?

• A. Golgi tendon organs
• B. Muscle spindles
• C. Pacinian corpuscles
• D. Nociceptors

Answer: (B)

Muscle spindles are stretch receptors located inside the muscle that monitor both how long the muscle is and how quickly it’s changing length. When the muscle is stretched, these receptors send signals to the spinal cord, triggering a reflex contraction of the same muscle. That contraction resists further stretch and protects the muscle from injury. Golgi tendon organs sense tension in the tendon and tend to limit force rather than sense length and speed of stretch; Pacinian corpuscles respond to vibration, and nociceptors respond to pain. So the sensor that detects changes in length and rate of stretching and triggers a protective contraction is the muscle spindle.

Muscle spindles are stretch receptors located inside the muscle that monitor both how long the muscle is and how quickly it’s changing length. When the muscle is stretched, these receptors send signals to the spinal cord, triggering a reflex contraction of the same muscle. That contraction resists further stretch and protects the muscle from injury. Golgi tendon organs sense tension in the tendon and tend to limit force rather than sense length and speed of stretch; Pacinian corpuscles respond to vibration, and nociceptors respond to pain. So the sensor that detects changes in length and rate of stretching and triggers a protective contraction is the muscle spindle.