Explanation

The cochlea is a spiral-shaped structure in the inner ear that converts sound vibrations into nerve signals. It contains fluid and thousands of tiny hair cells that bend when vibrations pass through. These hair cells trigger the auditory nerve to send messages to the brain.

When sound enters the ear, it makes the eardrum vibrate. Small bones called ossicles amplify these vibrations and pass them to the cochlea. The cochlea then translates the mechanical vibrations into electrical signals the brain can understand as sound.

The eardrum and ossicles receive and amplify sound but do not connect to the auditory nerve. The auditory canal is just the tube leading to the eardrum. Only the cochlea has the special hair cells that directly stimulate the auditory nerve.