The endolymph of the cochlear duct vibrates, causing the hair cell stereocilia to move against the tectorial membrane. The hair cell releases neurotransmitter during depolarization, generating an action potential to the cochlear nerve. Loud sounds produce vigorous vibrations of the organ of Corti, exciting a greater number of cells over a larger area. The brain interprets a higher frequency of action potentials as a loud sound. A sound causes a standing wave in the basilar membrane.
Some neurons continue to higher centers of the brain.
The temporal lobe is the site of conscious sound perception. The sense of equilibrium in humans is divided into static equilibrium and dynamic equilibrium The Saccule and Utricle Each of these chambers within the vestibule has a patch of hair cells and supporting cells called a macula. There are two such patches per ear, one in the saccule and one in the utricle. These help in the perception of the orientation of the head when the body is stationary. When the position of the head is moved, the otoliths shift, causing the hair cells to bend, and generate a nerve signal.