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 has fluid in it, which moves due to the vibrations and bends hairs on the outside of cells lining the cochlea. There are about 17,000 hair cells in each ear, so they really are tiny. They are not like the hair on your head. Some of these hair cells (the 'inner hair cells') create an electrical impulse (signal), which is sent along the auditory nerve to the brain.