Crista ampullaris

Crista ampullaris
*Anatomical terminology* [edit on Wikidata]

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 three specialized regions of the membranous labyrinth: the vestibular sacs and the semicircular ducts, which are the vestibular organs, as well as the cochlear duct, which is involved in the special sense hearing.

The semicircular canals are filled with endolymph, 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

Anatomy of hearing and balance

Outer ear

Auricle
- helix
- antihelix
- tragus
- antitragus
- intertragic notch
- earlobe
Ear canal
Auricular muscles
Eardrum
- umbo
- pars flaccida

Middle ear

Tympanic cavity	Medial structures oval window round window secondary tympanic membrane prominence of facial canal promontory of tympanic cavity Posterior structures mastoid cells aditus to mastoid antrum pyramidal eminence

Ossicles	Malleus superior ligament lateral ligament anterior ligament Incus superior ligament posterior ligament Stapes annular ligament Muscles stapedius tensor tympani

Auditory tube / Eustachian tube	Torus tubarius

Inner ear/
(membranous labyrinth,
bony labyrinth)

Auditory system/
Cochlear labyrinth

General cochlea	Vestibular duct Helicotrema Tympanic duct 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 tip links Tectorial membrane Sulcus spiralis externus internus Spiral limbus

Cells	Claudius cell Boettcher cell

Vestibular system/
Vestibular labyrinth

Vestibule	Utricle macula Saccule macula Kinocilium Otolith Vestibular aqueduct endolymphatic duct endolymphatic sac Ductus reuniens

Semicircular canals	Superior semicircular canal Posterior semicircular canal Horizontal semicircular canal Ampullary cupula Ampullae crista ampullaris

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