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 a spiral structure containing cilia (hair-like structures) and fluids that flow throughout the inner ear to help with the detection of the body orientation and sound transmission to the brain. All the cilia in the cochlea are connected to the brain via the auditory nerve.