Kinocilium

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Kinocilium
Dorlands/Elsevier	k_03/12471150

A kinocilium is a special structure on the apex of hair cells located in the sensory epithelium of the vertebrate inner ear.

Contents 1 Anatomy in humans 2 Anatomy in fish and frogs 3 References 4 External links 5 See also

[edit] Anatomy in humans

In the human ear, each hair cell has a single non-motile cilium known as the kinocilium. Cochlear hair cells have kinocilia that degenerate following maturation of the stereociliary bundle. It is believed that the kinocilium is important in delineating the anatomical asymmetry of stereocilia or in making some mechanical connections with the hair cells in which they persist.^[1]

[edit] Anatomy in fish and frogs

The apical surface of a sensory fish hair cell usually has numerous stereocilia and a single, much longer kinocilium. Deflection of the stereocilia toward or away from the kinocilium causes an increase or decrease in the firing rate of the sensory neuron innervating the hair cell at its basal surface.

Hair cells in fish and some frogs are used to detect water movements around their bodies. These hair cells are embedded in a jelly-like protrusion called cupula. The hair cells therefore can not be seen and do not appear on the surface of skin of fish and frogs.

[edit] References

1. ^ Nolte, John (2002). The human brain: an introduction to its functional anatomy. St. Louis: Mosby. ISBN 0-323-01320-1. 

[edit] External links

• http://www.unmc.edu/Physiology/Mann/pix_4b/hair_cell.gif

[edit] See also

• Fish anatomy
• Utricle
• Otolith

v • d • e Sensory system: Auditory and Vestibular systems Outer ear Pinna (Helix, Antihelix, Tragus, Antitragus, Earlobe) • Ear canal Middle ear Eardrum (Umbo) • Ossicles (Malleus, Incus & Stapes) • muscles (Stapedius, Tensor tympani) • Eustachian tube (Torus tubarius) Inner ear/Labyrinth Bony labyrinth (Vestibule) • Membranous labyrinth Oval window → Scala vestibuli / Reissner's/vestibular membrane, Helicotrema and Scala tympani / Basilar membrane (Perilymph) → Round window Cochlea: Modiolus • Cochlear duct / scala media (Endolymph, Stria vascularis, Spiral ligament, Organ of Corti), Olivocochlear system Organ of Corti: Stereocilia • Sulcus spiralis (externus, internus) • Limbus spiralis to brain (auditory) Tectorial membrane → Hair cells → Spiral ganglion → Cochlear nerve VIII → Cochlear nuclei → Trapezoid body → Superior olivary nuclei → Lateral lemniscus → Inferior colliculi → Medial geniculate nuclei → Auditory radiations → Primary auditory cortex Vestibular system Static/translations: Utricle (Macula) – Saccule (Macula, Endolymphatic sac, Endolymphatic duct) – Kinocilium – Otolith Kinetic/rotations: Semicircular canals (Superior, Posterior, Horizontal) • Cupula • Ampullae (Crista ampullaris) to brain (vestibular) Vestibular nerve VIII → Vestibular nuclei, Flocculonodular lobe Vestibular nuclei → Vestibulospinal tract, Ventral posterolateral nucleus → Vestibular cortex