The inner ear is an organ located deep within the temporal bone, which is the bone of the skull on both sides of the head above the outer ear. The inner ear has two main structures: the semicircular canals and the cochlea.
The semicircular canals do not contribute to hearing but assist in maintaining balance as we move. The cochlea is the hearing organ of the inner ear, which is a fluid-filled structure that looks like a snail’s shell. The cochlea changes the mechanical vibrations from the eardrum and the ossicles into a sequence of electrical impulses. Sensory cells, called hair cells, bend in the cochlea as the fluid is disrupted by the mechanical vibrations. This bending of the hair cells causes electrical signals to be sent to the brain by way of the auditory nerve. The cochlea is arranged by frequency, much like a piano, and encodes sounds from 20Hz (low pitch) to 20,000Hz (high pitch) in humans.