When a sound is made, the sound waves travel through the air and enter the ear through the ear canal. The sound waves travel through the outer ear and vibrate against the tympanic membrane (or eardrum). The tympanic membrane transmits vibrations through the small bones of the middle ear to the cochlea. The cochlea is a delicate, spiral-shaped structure with tiny hair cells.
These hair cells are connected to the auditory nerve. Movement of these cells sends electrical impulses to the auditory nerve. The auditory nerve sends these impulses to the brain. When the impulses reach the brain, it processes the information and hearing occurs.