Questions: Which of the following describes a Golgi tendon organ? A sensitive to increases in muscular tension B monitors changes in myscle length (C) runs parallel to extrafusal muscle fibers D located within intrafusal muscle fibers

The answer is the first one (A): sensitive to increases in muscular tension.

Explanation for each option:

A. Sensitive to increases in muscular tension - Correct. The Golgi tendon organ is a proprioceptive sensory receptor organ that senses changes in muscle tension. It is located at the junction of muscle and tendon and is responsible for monitoring and responding to changes in tension, helping to prevent muscle damage from excessive force.

B. Monitors changes in muscle length - Incorrect. This function is primarily associated with muscle spindles, not Golgi tendon organs. Muscle spindles are sensitive to changes in muscle length and the rate of that change.

C. Runs parallel to extrafusal muscle fibers - Incorrect. Golgi tendon organs are located in series with muscle fibers, not parallel. They are found at the junction between muscle fibers and tendons.

D. Located within intrafusal muscle fibers - Incorrect. Golgi tendon organs are not located within intrafusal muscle fibers; they are located in the tendons. Intrafusal fibers are part of the muscle spindle apparatus.

In summary, the Golgi tendon organ is sensitive to increases in muscular tension, making option A the correct description.