Crista ampullaris

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Crista ampullaris

Semicircular canal: ampulla at medium magnification with a hemotoxylin & eosin stain

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

Background

The inner ear comprises two specialized regions of the membranous labyrinth: the saccule and the utricle, as well as the cochlear duct, which is involved in the special sense hearing.

The Semicircular canals are filled with perilymph, and also contain an inner membranous sleeve that form semicircular ducts. The semicircular ducts are filled with endolymph, and contain the crista ampullaris. The receptor cells located in the semicircular ducts are innervated by the eighth cranial nerve, aka vestibulocochlear nerve (more specifically the vestibular portion).

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. The hair cells respond by stimulating neurons that innervate them.

References

Ovalle, William (2008). Netter's Essential Histology. Philadelphia, PA USA: Saunders Elsevier. p. 448. ISBN 978-1-929007-86-8.

External links

Sensory system: Auditory and Vestibular systems (TA A15.3, TH 3.11.09, GA 10.1029)

Outer ear

Pinna (Helix, Antihelix, Tragus, Antitragus, Incisura anterior auris, Earlobe)
Ear canal
Auricular muscles

Eardrum (Umbo
Pars flaccida)

Middle ear

Tympanic cavity	Labyrinthine wall/medial: Oval window Round window Secondary tympanic membrane Prominence of facial canal Promontory of tympanic cavity Membranous wall/lateral Mastoid wall/posterior: Mastoid cells Aditus to mastoid antrum Pyramidal eminence Carotid wall/anterior Tegmental wall/roof: Epitympanic recess Jugular wall/floor

Ossicles	Malleus (Neck of malleus, Superior ligament of malleus, Lateral ligament of malleus, Anterior ligament of malleus) Incus (Superior ligament of incus, Posterior ligament of incus) Stapes (Anular ligament of stapes)

Muscles	Stapedius Tensor tympani

Eustachian tube	Bony part of pharyngotympanic tube Cartilage of pharyngotympanic tube (Torus tubarius)

Inner ear/
(membranous labyrinth,
bony labyrinth)

Auditory system
Cochlear labyrinth

General cochlea	Scala vestibuli Helicotrema Scala tympani Modiolus Cochlear cupula

Perilymphatic space	Perilymph Cochlear aqueduct

Cochlear duct / scala media	Reissner's/vestibular membrane Basilar membrane Reticular membrane Endolymph Stria vascularis Spiral ligament Organ of Corti: Stereocilia Tectorial membrane Sulcus spiralis (externus, internus) Spiral limbus

Cells	Claudius cell Boettcher cell

Vestibular system/
Vestibular labyrinth

Static/translations/vestibule/endolymphatic duct: Utricle (Macula)
Saccule (Macula, Endolymphatic sac)
Kinocilium
Otolith
Vestibular aqueduct
Canalis reuniens

Kinetic/rotations: Semicircular canals (Superior, Posterior, Horizontal)
Ampullary cupula
Ampullae (Crista ampullaris)

M: EAR

anat (e/p)/phys/devp

noco/cong, epon

proc, drug (S2)

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