 Inner ear

The inner ear contains fluid-filled sensory structures for hearing and balance. In the cochlea, motion transmitted from the middle ear creates a traveling disturbance along the basilar membrane. Movement of sensory hair cells bends their stereocilia, changing mechanically gated ion-channel opening and producing an electrical response.^[ref]

The mechanical response varies along the cochlea, so position contributes to frequency selectivity. The vestibular part of the inner ear instead detects head motion and orientation. The distinction is anatomical and functional: detecting a sound frequency and detecting a rotation of the head use related mechanosensory principles in different structures. Mechanical input, hair-cell response and activity in the associated sensory neurons are successive measurable stages.

The inner ear is a crucial component of the auditory and vestibular systems in humans and many other animals. It is located deep within the temporal bone of the skull and consists of several key structures: 1. **Cochlea**: A spiral-shaped, fluid-filled structure that is responsible for hearing. It converts sound vibrations into neural signals. The cochlea contains hair cells that detect sound waves; these cells trigger nerve impulses that are sent to the brain.