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 auditory nerve and the vestibular nerve, which carries balance information from the semicircular canals to the brain, join together as they pass through the bony canals of your skull. Together, they are called the 8th cranial nerve, or the Vestibulocochlear nerve.