What are the receptors called that detect stretch in the stretch reflex?

• A. Golgi tendon organs
• B. Pacinian corpuscles
• C. Meissner's corpuscles
• D. Muscle spindles

Answer: (D)

Verified step by step guidance

1. Understand the stretch reflex: The stretch reflex is a protective mechanism that prevents overstretching of muscles. It is initiated when a muscle is stretched, and the receptors involved detect this stretch.
2. Identify the role of muscle spindles: Muscle spindles are specialized sensory receptors located within the muscle fibers. They are responsible for detecting changes in muscle length and the rate of stretch.
3. Differentiate muscle spindles from other receptors: Golgi tendon organs detect tension in tendons, Pacinian corpuscles detect pressure and vibration, and Meissner's corpuscles detect light touch. None of these are involved in detecting stretch in the stretch reflex.
4. Relate muscle spindles to the stretch reflex: When a muscle spindle detects stretch, it sends signals via sensory neurons to the spinal cord. This triggers a reflexive contraction of the stretched muscle to counteract the stretch.
5. Conclude the correct receptor: Based on the function and location, muscle spindles are the correct receptors involved in detecting stretch during the stretch reflex.