Spiral ganglion

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Spiral ganglion
Transverse section of the cochlear duct of a fetal cat. (Ganglion spirale is labeled at top, second from left.)
Latin	ganglion spirale
Gray's	subject #228 1051
System
MeSH	A08.340.390.800
Part of the cochlear division of the acoustic nerve, highly magnified.

The spiral ganglion is the group of nerve cells that serve the sense of hearing by sending a representation of sound from the cochlea to the brain. The cell bodies of the spiral ganglion neurons are found in the spiral structure of the cochlea.

Contents 1 Development 2 Anatomy 3 References 4 External links

[edit] Development

The rudiment of the acoustic nerve appears about the end of the third week as a group of ganglion cells closely applied to the cephalic edge of the auditory vesicle. The ganglion gradually splits into two parts, the vestibular ganglion and the spiral ganglion. The proximal fibers of the spiral ganglion form the cochlear nerve.

[edit] Anatomy

Cells found in the spiral ganglion are strung along the bony core of the cochlea, and send projections into the central nervous system (CNS). These cells are bipolar first-order neurons of the auditory system. Their dendrites make synaptic contact with the base of hair cells, and their axons are bundled together to form the auditory portion of eighth cranial nerve. The number of neurons in the spiral ganglion is estimated to be about 35,000–50,000.^[1]

[edit] References

1. ↑ Mark F. Bear, Barry W. Connors, and Michael A. Paradiso (2006). Neuroscience, Lippincott Williams & Wilkins.

[edit] External links

• Slide and overview at anatomy.dal.ca
• Slide at cytochemistry.net
• Image at University of New England, Maine

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

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) • Stapedius • Tensor tympani • Eustachian tube (Torus tubarius)
Inner ear/Labyrinth	Bony labyrinth (Vestibule) • Membranous labyrinth Oval window • Helicotrema • Round window Cochlea: Spiral ganglion • Modiolus • Cochlear duct/scala media (Endolymph, Stria vascularis, Spiral ligament, Organ of Corti) • Scala vestibuli and Scala tympani (Perilymph) Reissner's/vestibular membrane • Basilar membrane • Tectorial membrane Organ of Corti: Hair cells • Stereocilia • Sulcus spiralis (externus, internus) • Limbus spiralis
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)
Brain (auditory)	Cochlear nerve VIII → Cochlear nuclei → Superior olivary nuclei → Lateral lemniscus → Inferior colliculi → Medial geniculate nuclei → Primary auditory cortex

This page uses content from the English-language version of Wikipedia. The original article was at Spiral ganglion. The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.