同: 蝸牛神経

WordNet

any bundle of nerve fibers running to various organs and tissues of the body (同)nervus
the snail-shaped tube (in the inner ear coiled around the modiolus) where sound vibrations are converted into nerve impulses by the organ of Corti
of or relating to the cochlea of the ear; "cochlear implant"
control of your emotions; "this kind of tension is not good for my nerves"

PrepTutorEJDIC

〈C〉『神経』 / 〈C〉《複数形で》『神経過敏』,いらだち / 〈U〉『勇気』,度胸(courage) / 〈U〉《時にa ~》厚かましさ,ずぶとさ;無礼 / 〈C〉葉脈;(昆虫の)翅脈(しみゃく) / 〈人,特に自分〉‘に'力を与える,‘を'元気づける
(耳の)蝸牛穀(かぎゅうかく)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/07 00:24:37」(JST)

wiki en

The cochlear nerve (also auditory or acoustic nerve) is one of two parts of the vestibulocochlear nerve, a cranial nerve present in amniotes. The cochlear nerve carries auditory sensory information from the cochlea of the inner ear directly to the brain. The other portion of the vestibulocochlear nerve is the vestibular nerve, which carries spatial orientation information to the brain from the semicircular canals.

Anatomy and connections

In terms of anatomy, an auditory nerve fiber is either bipolar or unipolar, with its distal projection being called the peripheral process, and its central projection being called the axon; these two projections are also known as the "peripheral axon" and the "central axon", respectively. The peripheral process is sometimes referred to as a dendrite, although that term is somewhat inaccurate. Unlike the typical dendrite, the peripheral process generates and conducts action potentials, which then "jump" across the cell body (or soma) and continue to propagate along the central axon. In this respect, auditory nerve fibers are somewhat unique in that action potentials pass through the soma. Both the peripheral process and the axon are myelinated.

In humans, the number of nerve fibers within the cochlear nerve averages around 30,000.^[1] The number of fibers varies significantly across species; for example, the domestic cat has some 50,000 fibers. The peripheral axons of auditory nerve fibers form synaptic connections with the hair cells of the cochlea via ribbon synapses using the neurotransmitter glutamate. The central axons form synaptic connections with cells in the cochlear nucleus of the brainstem. The cell bodies of the cochlear nerve lie within the cochlea and collectively form the spiral ganglion, named for the spiral shape it inherits from the cochlea. The terms "cochlear nerve fiber" and "spiral ganglion cell" are used, to some degree, interchangeably, although the former may be used to more specifically refer to the central axons of the cochlear nerve. These central axons exit the cochlea at its base and form a nerve trunk, which, in humans, is approximately one inch long. The cochlear nerve projects centrally to the brainstem, where its fibers synapse with the cell bodies of the cochlear nucleus. A good anatomical description of human auditory nerve fibers is provided by Spoendlin and Schrott (1985). Important earlier work was done by Schuknecht.

Types of neurons

In mammals, cochlear nerve fibers are classified as either type I or type II.

Type I neurons make up 90-95% of the neurons and innervate the inner hair cells. They have relatively large diameters, are bipolar, and are myelinated. Each type I axon innervates only a single inner hair cell, but each inner hair cell is innervated by up to 30 such nerve fibers, depending on species and location within the cochlea.
Type II neurons make up the remaining 5-10% of the neurons and innervate the outer hair cells. They have relatively small diameters, are unipolar, and are unmyelinated.

Cochlear nuclear complex

In mammals, the axons from each cochlear nerve terminate in the cochlear nuclear complex that is ipsilaterally located in the medulla of the brainstem. The cochlear nucleus is the first 'relay station' of the central auditory system and receives mainly ipsilateral afferent input.

The three major components of the cochlear nuclear complex are (see figure below):

the dorsal cochlear nucleus (DCN)
the anteroventral cochlear nucleus (AVCN)
the posteroventral cochlear nucleus (PVCN)

Each of the three cochlear nuclei are tonotopically organized. The axons from the low-frequency region of the cochlea project to the ventral portion of the dorsal cochlear nucleus and the ventrolateral portions of the anteroventral cochlear nucleus. The axons from the high-frequency region project to the dorsal portion of the anteroventral cochlear nucleus and the uppermost dorsal portions of the dorsal cochlear nucleus. The axons from the intermediate frequency region project to intermediate targets, such that tonotopy is preserved between the cochlea and the cochlear nuclei.

References

^ Spoendlin H, Schrott A (1989). "Analysis of the human auditory nerve". Hear Res 43 (1): 25–38. doi:10.1016/0378-5955(89)90056-7. PMID 2613564.

Additional images

Ear anatomy
Cochlear nucleus innervated by a branching auditory nerve fibre
Terminal nuclei of the vestibular nerve, with their upper connections.
Transverse section of the cochlear duct of a fetal cat.
Floor of ductus cochlearis.
Diagrammatic longitudinal section of the cochlea
Organ of corti

External links

Illustration at cytochemistry.net
Gray's page #1059

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 成人における第三脳神経（動眼神経）麻痺 third cranial nerve oculomotor nerve palsy in adults
2. 神経伝導検査の概要 overview of nerve conduction studies
3. 下肢末梢神経症候群の概要 overview of lower extremity peripheral nerve syndromes
4. 上肢末梢神経症候群の概要 overview of upper extremity peripheral nerve syndromes
5. 小児における第3脳神経（動眼神経）麻痺 third cranial nerve oculomotor nerve palsy in children

English Journal

Usefulness of measuring electrically evoked auditory brainstem responses in children with inner ear malformations during cochlear implantation.

Minami SB1, Takegoshi H, Shinjo Y, Enomoto C, Kaga K.
Acta oto-laryngologica.Acta Otolaryngol.2015 Oct;135(10):1007-1015. Epub 2015 Jun 10.
CONCLUSIONS: EABR is a reliable and effective way of objectively confirming device function and implant-responsiveness of the peripheral auditory neurons up to the level of the brainstem in cases of inner ear malformation.OBJECTIVE: To investigate the usefulness of measuring the intra-operative elec
PMID 26062093

Cell-specific accumulation patterns of gentamicin in the guinea pig cochlea.

Heinrich UR1, Schmidtmann I2, Strieth S1, Helling K3.
Hearing research.Hear Res.2015 Aug;326:40-8. doi: 10.1016/j.heares.2015.03.010. Epub 2015 Apr 13.
Intratympanic gentamicin therapy has become a popular treatment modality for Ménière's disease (MD) through controlled elimination of vertigo spells caused by the balance organ. However, the known ototoxic properties of aminoglycosides lead to cochlear damage. In order to gain more information abo
PMID 25882166

Determining compliance of ear CT scan with interaoperative findings in deaf children with cochlear implantation.

Mohammad A1, Mohammad Bagher S2, Mahdi M2, Zahra A3.
International journal of pediatric otorhinolaryngology.Int J Pediatr Otorhinolaryngol.2015 Aug;79(8):1253-6. doi: 10.1016/j.ijporl.2015.05.024. Epub 2015 May 29.
INTRODUCTION: Defecated or impaired hair cell function of the cochlea causes deafness. Cochlear implantation allows transmission of sound information through central auditory pathways using direct electric stimulation of auditory nerve dendrites. Using radiologic imaging, including CT scan is very h
PMID 26066852

Japanese Journal

Auditory perception induced by optical stimulation to the cochlear nerve

MATSUI Suguru,KOBAYASI Kohta I.,RIQUIMAROUX Hiroshi
聴覚研究会資料 = Proceedings of the auditory research meeting 44(8), 485-489, 2014-11-27
NAID 40020295221

Preoperative Characteristics of Auditory Brainstem Response in Acoustic Neuroma with Useful Hearing: Importance as a Preliminary Investigation for Intraoperative Monitoring

AIHARA Noritaka,MURAKAMI Shingo,TAKAHASHI Mariko,YAMADA Kazuo
Neurologia medico-chirurgica 54(4), 267-271, 2014
… Monitoring cochlear nerve action potential (CNAP) may be useful because CNAP could be detected in 4 of 5 wave I only patients. … Because the latency of wave V is already prolonged before surgery, to estimate delay in wave V latency during surgery probably underestimates cochlear nerve damage. … Recording intraoperative ABR is indispensable to avoid cochlear nerve damage and to provide information for surgical decisions. …
NAID 130003391991

鼓室に逸脱する内頸動脈走行異常を合併する人工内耳手術の経験

木戸口正典,南修司郎,竹腰英樹,加我君孝
Otology Japan 23(3), 243-247, 2013-07-25
NAID 10031189733

Related Pictures

★リンクテーブル★

リンク元	「蝸牛神経」
拡張検索	「vestibulocochlear nerve」
関連記事	「nerve」「cochlear」

「蝸牛神経」

Cochlear nerve
	Diagrammatic longitudinal section of the cochlea. (Cochlear nerve is in center, shown as striped.)
	Part of the cochlear division of the acoustic nerve, highly magnified.
Details
Latin	nervus cochlearis
From	Vestibulocochlear nerve
Identifiers
Gray's	p.906
MeSH	A08.800.800.120.910.120
TA	A14.2.01.133
FMA	53431
	Anatomical terms of neuroanatomy