Sound waves enter the ear through the ear canal. Then they strike the eardrum. The eardrum is what separates the ear canal from the middle ear.

The sound waves make the eardrum vibrate. The vibrations move to the bones of the middle ear. This boosts the sound and sends it to the inner ear.

The inner ear is a fluid-filled, curved space that is sometimes called the labyrinth. It contains the cochlea, the main sensory organ of hearing. Sound vibrations cause the fluid in the inner ear to move. This bends tiny hair cells (cilia) in the cochlea. The movement of the hair cells creates nerve impulses. These nerve impulses then travel along the cochlear nerve to the brain and are heard as sound.