Sound waves collected by the outer ear are channeled along the ear canal to the eardrum. When sound waves hit the eardrum, the impact creates vibration, which in turn causes three bones in the middle ear to move.
The smallest of these bones, the stapes, fits into the oval window between the middle and the inner ear.
When the oval window vibrates, fluid in the inner ear transmits these vibrations to a delicate snail shape structure called the cochlea.
The bending of hair cells in the cochlea sets off nerve impulses, which pass through the auditory nerve to the hearing center of the brain. Here it is translated into signals the brain can recognize.