What structure senses linear acceleration within the vestibular system?

The correct choice is the otolith organs, which are a vital component of the vestibular system responsible for detecting linear acceleration and the effects of gravity. The otolith organs consist of two structures known as the utricle and saccule. These structures contain sensory hair cells embedded in a gelatinous layer, which is weighted down by tiny crystals called otoliths. When a person experiences linear acceleration, such as moving forward in an airplane or up an elevator, the otoliths shift in response to the change in motion. This shift affects the hair cells and generates signals that are sent to the brain, allowing us to perceive our position and acceleration relative to gravity.

In contrast, the semicircular canals are primarily responsible for sensing rotational movements rather than linear acceleration. They contain fluid that moves within the canals when the head rotates, stimulating hair cells to detect angular motion. The cochlea is involved in hearing and processes sound waves rather than motion, while the auditory nerve transmits sound signals from the cochlea to the brain, focusing solely on auditory functions. Therefore, the otolith organs are the correct structures for sensing linear acceleration within the vestibular system.