Definition of cocaine. : a bitter crystalline alkaloid C17H21NO4 obtained from coca leaves that is used especially in the form of its hydrochloride medically as a topical anesthetic and illicitly for its euphoric effects and that may result in a compulsive psychological need.
The inner hair cells transform the sound vibrations in the fluids of the cochlea into electrical signals that are then relayed via the auditory nerve to the auditory brainstem and to the auditory cortex.
The cochlea is the inner ear organ of hearing. The cochlea is lined by thousands of very small nerve endings. When sound waves cause the fluids in the cochlea to move, it activates the nerve endings. There are many causes of cochlear hearing loss. Some patients benefit from a hearing aid.