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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.
The term for this is positional alcohol nystagmus (PAN): PAN I - The alcohol concentration is higher in the blood than in the vestibular system, hence the endolymph is relatively dense. PAN II - The alcohol concentration is lower in the blood than in the vestibular system, hence the endolymph is relatively dilute.
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 ...
Eponymous medical signs are those that are named after a person or persons, usually the physicians who first described them, but occasionally named after a famous patient. This list includes other eponymous entities of diagnostic significance; i.e. tests, reflexes, etc.
Within the ampulla is a mound of hair cells and supporting cells called crista ampullaris. These hair cells have many cytoplasmic projections on the apical surface called stereocilia which are embedded in a gelatinous structure called the cupula. As the head rotates, the duct moves, but the endolymph lags behind owing to inertia. This deflects ...
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.
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]