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The crista ampullaris itself is a cone-shaped structure, covered in receptor cells called "hair cells". Covering the crista ampullaris is a gelatinous mass called the cupula . Upon angular acceleration (rotation), the endolymph within the semicircular duct deflects the cupula against the hair cells of the crista ampullaris.
As a result, the cupula is deflected opposite the direction of head movement. As the endolymph pushes the cupula, the stereocilia is bent as well, stimulating the hair cells within the crista ampullaris. After a short time of continual rotation however, the endolymph's acceleration normalizes with the rate of rotation of the semicircular ducts.
In the semicircular canals, the hair cells are found in the crista ampullaris, and the stereocilia protrude into the ampullary cupula. Here, the stereocilia are all oriented in the same direction. In the otoliths, the hair cells are topped by small, calcium carbonate crystals called otoconia. Unlike the semicircular ducts, the kinocilia of hair ...
The delayed movement of the endolymph bends and activates the cupula. When the cupula bends, the connected stereocilia bend along with it, activating chemical reactions in the hair cells surrounding crista ampullaris and eventually create action potentials carried by the vestibular nerve signaling to the body that it has moved in space.
The saccule is the smaller sized vestibular sac (the utricle being the other larger size vestibular sac); it is globular in form, and lies in the recessus sphæricus near the opening of the scala vestibuli of the cochlea.
Kinocilia are present in the crista ampullaris of the semicircular ducts and the sensory maculae of the utricle and saccule. [1] One kinocilium is the longest cilium located on the hair cell next to 40–70 stereocilia. During movement of the body, the hair cell is depolarized when the stereocilia move toward the kinocilium.
Rudolph Bedford, MD, a board0certified gastroenterologist at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the study, described the uncertainty of living ...
Cross-section through the spiral organ of Corti at greater magnification, showing position of the hair cells on the basement membrane. The organ of Corti is located in the scala media of the cochlea of the inner ear between the vestibular duct and the tympanic duct and is composed of mechanosensory cells, known as hair cells. [2]