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 fluid-filled inner ear transduces sound vibrations into neural signals that are sent to the brain for processing. The cochlea is the major sensory organ of hearing within the inner ear. Hair cells within the cochlea perform the transduction of sound waves.