The vestibular system allows your eyes to adjust when your head moves through the use of three semicircular canals and two baglike structures. When the head tilts or moves, calcium carbonate particles or a jellylike substance push against hair cells in the structures, causing action potentials that travel to the brainstem and cerebellum to help keep your eyes focused.
2. Vestibular Sensations When you move your head, the organs of the vestibular system adjust the movement and allow your eyes to adjust as well. For example, when your head moves left, your eyes move right and when your head moves right your eyes move left. This allows you to keep your eyes focused on what you want to see.
3. Vestibular Sensations The vestibular organ looks like it is part of the structures used for hearing and is attached to the hearing structures. It is composed of three semicircular canals. Calcium carbonate particles called otoliths lie next to the hair cells (similar to the hair cells used in hearing) that are the receptor cells for vestibular sensations. When the head tilts in different directions, the otoliths push against sets of hair cells and cause them to be excited and produce action potentials.
4. Vestibular Sensations The semicircular canals are on three different planes, and they are filled with a jellylike substance and lined with the hair cells. During head movement, the jellylike substance also pushes against the hair cells. This causes action potentials to be produced, and they travel to the brainstem and cerebellum. Two baglike structures, known as saccule and utricle, are also part of the vestibular system.
5. Vestibular Sensations The vestibular system, showing the saccule, utricle and three semicircularcanals.
