Crista ampullaris

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Crista ampullaris
Dorlands/Elsevier	c_62/12266540

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The crista ampullaris is the sensory organ of balance located in the semicircular canal of the inner ear. The function of the crista ampullaris is to sense angular acceleration and deceleration.

[edit] Background

The inner ear is comprised of 2 specialized regions of the membranous labyrinth: the saccule and the utricle.

• The saccule gives rise to the cochlear duct, which is involved in the special sense hearing.
• The utricle gives rise to the semicircular canals, which is involved in "equilibrium/balance".

The receptor cells located in the semicircular canal are innervated by the eighth cranial nerve, aka vestibulocochlear nerve (more specifically the vestibular portion).

[edit] External links

• http://faculty.une.edu/com/abell/histo/CristaAmp.jpg
• http://www.kumc.edu/instruction/medicine/anatomy/histoweb/eye_ear/ear04.htm
• http://www.anatomyatlases.org/MicroscopicAnatomy/Section16/Plate16314.shtml
• http://www.med.uiuc.edu/histo/small/atlas/objects/1296.htm
• http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab11/Ear/EXAMPLES/Excrista.htm

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