Cochlear nerve - wikipedia Cochlear nerve 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 From Vestibulocochlear nerve Identifiers Latin nervus cochlearis MeSH A08. 800.800. 120.910. 120 TA A14. 2.01. 133 FMA 53431 Anatomical terms of neuroanatomy ( edit on Wikidata ) The cochlear nerve ( also auditory or acoustic nerve ) is one of two parts of the vestibulocochlear nerve, a cranial nerve present in amniotes, the other part being the vestibular nerve. 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, also known as semicircular ducts. Contents 1 Anatomy and connections 2 Types of neurons 3 Cochlear nuclear complex 4 See also 5 References 6 Additional images 7 External links 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 unusual in that action potentials pass through the soma. Both the peripheral process and the axon are myelinated. In humans, there are on average 30,000 nerve fibers within the cochlear nerve. The number of fibers varies significantly across species ; the domestic cat, for example, has an average of 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 shares with the cochlea. These central axons exit the cochlea at its base and form a nerve trunk, which, in humans, is approximately one inch long. This travels in parallel with the vestibular nerves through the internal auditory canal, through which it connects to the brainstem. There, its fibers synapse with the cell bodies of the cochlear nucleus. 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. See also Cochlear implant References Jump up ^ Spoendlin H, Schrott A ( 1989 ). `` Analysis of the human auditory nerve ''. Hear Res. 43 ( 1 ) : 25 -- 38. PMID 2613564. doi : 10.1016 / 0378 - 5955 ( 89 ) 90056 - 7. 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 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 Physiology of balance and hearing Hearing General Auditory system Bone conduction Otoacoustic emission Tullio phenomenon Pathway inner ear : Hair cells → Spiral ganglion → Cochlear nerve → pons : Cochlear nucleus ( Anterior, Dorsal ) → Trapezoid body → Superior olivary nuclei → midbrain : Lateral lemniscus → Inferior colliculi → thalamus : Medial geniculate nuclei → cerebrum : Acoustic radiation → Primary auditory cortex Balance General Vestibular system Pathway inner ear : Vestibular nerve → pons : Vestibular nuclei ( Medial vestibular nucleus, Lateral vestibular nucleus ) cerebellum : Flocculonodular lobe spinal cord : Vestibulospinal tract ( Medial vestibulospinal tract, Lateral vestibulospinal tract ) thalamus : Ventral posterolateral nucleus cerebrum : Vestibular cortex Vestibulo - oculomotor fibers The cranial nerves terminal Nuclei Septal nuclei Course no significant branches olfactory Nuclei Anterior olfactory nucleus Course olfactory bulb olfactory tract optic Nuclei Lateral geniculate nucleus Course optic chiasm optic tract oculomotor Nuclei Oculomotor nucleus Edinger - Westphal nucleus Branches superior parasympathetic root of ciliary ganglion / ciliary ganglion inferior trochlear Nucleus Branches no significant branches trigeminal Nuclei PSN Spinal trigeminal nucleus MN TMN Course trigeminal ganglion Branches ophthalmic maxillary mandibular abducens Nucleus Branches no significant branches facial near origin intermediate nerve geniculate inside facial canal greater petrosal pterygopalatine ganglion nerve to the stapedius chorda tympani lingual nerve submandibular ganglion at stylomastoid foramen posterior auricular suprahyoid digastric stylohyoid parotid plexus temporal zygomatic buccal mandibular cervical Nuclei Facial motor nucleus Solitary nucleus Superior salivary nucleus vestibulocochlear Nuclei Vestibular nuclei Cochlear nuclei cochlear nerve striae medullares lateral lemniscus vestibular Scarpa 's ganglion glossopharyngeal before jugular fossa ganglia superior inferior after jugular fossa tympanic tympanic plexus lesser petrosal otic ganglion stylopharyngeal branch pharyngeal branches tonsillar branches lingual branches carotid sinus Nuclei Nucleus ambiguus Inferior salivatory nucleus Solitary nucleus vagus before jugular fossa ganglia superior inferior after jugular fossa meningeal branch auricular branch neck pharyngeal branch pharyngeal plexus superior laryngeal external internal recurrent laryngeal ( inferior ) superior cervical cardiac thorax inferior cardiac pulmonary vagal trunks anterior posterior abdomen celiac renal hepatic anterior gastric posterior gastric Nuclei Nucleus ambiguus Dorsal nucleus of vagus nerve Solitary nucleus accessory Nuclei Nucleus ambiguus Spinal accessory nucleus cranial spinal hypoglossal Nucleus Branches lingual Retrieved from `` https://en.wikipedia.org/w/index.php?title=Cochlear_nerve&oldid=794793924 '' Categories : Auditory system Vestibulocochlear nerve Hidden categories : Medicine infobox template using GraySubject or GrayPage Talk Contents About Wikipedia Català Español فارسی Français Nederlands Português Svenska తెలుగు Edit links This page was last edited on 10 August 2017, at 02 : 40. 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Question: where does the cochlear nerve transmit impulses to
Answer: the cochlear nucleus of the brainstem