Final answer:
When muscle spindles detect excessive stretching, they initiate the stretch reflex to induce muscle contraction, ensuring the protection and maintenance of muscle length.
Step-by-step explanation:
If a stretch is executed too fast or lengthens the tissue too much, muscle spindles provide feedback to the muscle to contract. This is known as the stretch reflex. When a skeletal muscle is stretched, a receptor called a muscle spindle is activated. The muscle spindle sends a signal to the muscle to contract and prevent excessive stretching of the tissue. The muscle spindles are stretch receptors that detect the degree of stretch and signal for the muscle to contract to prevent injury and maintain muscle length. In contrast, the Golgi tendon organs are tension receptors that detect the force of muscle contraction and would lead to relaxation of the muscle to prevent damage from the excessive force. Therefore, the correct answer to the question is b) Stretch.