Which receptors sense movement of the tendons that connect muscle to bone?

• A. Muscle spindles
• B. Golgi tendon organs
• C. Pacinian corpuscles
• D. Free nerve endings

Answer: (B)

Movement of the tendons is sensed by Golgi tendon organs. These receptors are located in the tendon near where it meets the muscle and are arranged in series with muscle fibers. They detect changes in tendon tension that occur when the muscle contracts, providing the nervous system with information about the force being generated. If tension gets too high, they trigger a protective reflex that relaxes the muscle to prevent damage. By contrast, muscle spindles monitor muscle length and how quickly it changes, Pacinian corpuscles respond to vibration and deep pressure, and free nerve endings carry nonspecific pain or temperature signals, not tendon movement.