Which of the following structures is NOT involved in dynamic equilibrium?

The cochlea is not involved in dynamic equilibrium; it is primarily associated with the sense of hearing. The cochlea contains hair cells that detect sound waves and convert them into neural signals for the auditory cortex, but it does not play a role in balance or the perception of motion.

In contrast, the utricle, saccule, and ampulla are all key components of the vestibular system, which is responsible for maintaining equilibrium and balance. The utricle and saccule detect linear accelerations and the position of the head relative to gravity, while the ampulla, located in the semicircular canals, detects rotational movements of the head. Together, these structures help the body understand its position and motion in three-dimensional space, essential for dynamic equilibrium.