Final answer:
Golgi tendon organs are tension receptors located in the tendons and protect muscles from excessive contraction forces. Muscle spindles, found within the muscle belly, detect muscle stretch and maintain optimal length through stretch reflexes. Both are vital for proprioception and muscle coordination.
Step-by-step explanation:
Contrary to the initial statement, Golgi tendon organs are found in the tendons of muscles, not in the belly of the muscle. These organs are tension receptors that detect the force of muscle contraction. In contrast, muscle spindles are stretch receptors located within the belly of a muscle that sense changes in muscle length.
The muscle spindle is involved in maintaining optimal muscle length through the stretch reflex, whereas the Golgi tendon organ monitors and prevents excessive contraction force, potentially protecting the muscle from damage. The primary responsibility of the muscle spindle is to trigger contractions that maintain muscle tone and prevent muscle damage from over-stretching.
Golgi tendon organs, on the other hand, provide a safety mechanism against excessive tension by triggering a reflex that causes the muscle to relax when too much force is applied. Both types of receptors play crucial roles in proprioception, sending signals related to muscle stretch and tension to the cerebellum, which is critical for the coordination of muscle movement.