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Nerve: Vestibulocochlear nerve | ||
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The course and connections of the facial nerve in the temporal bone | ||
Inferior view of the human brain, with the cranial nerves labelled. | ||
Latin | Nervus vestibulocochlearis | |
Gray's | subject #203 | |
Innervates | ||
From | ||
To | Cochlear nerve, vestibular nerve | |
MeSH | A08.800.800.120.910 |
Cranial Nerves |
---|
CN 0 - Cranial nerve zero |
CN I - Olfactory |
CN II - Optic |
CN III - Oculomotor |
CN IV - Trochlear |
CN V - Trigeminal |
CN VI - Abducens |
CN VII - Facial |
CN VIII - Vestibulocochlear |
CN IX - Glossopharyngeal |
CN X - Vagus |
CN XI - Accessory |
CN XII - Hypoglossal |
The vestibulocochlear nerve (auditory vestibular nerve)[1] is the eighth of twelve cranial nerves, and is responsible for transmitting sound and equilibrium (balance) information from the inner ear to the brain. The vestibulocochlear nerve is derived from the embryonic otic placode.
Structure and function[]
This is the nerve along which the sensory cells (the hair cells) of the inner ear transmit information to the brain. It consists of the cochlear nerve, carrying information about hearing, and the vestibular nerve, carrying information about balance. It emerges from the pontomedullary junction and exits the inner skull via the internal acoustic meatus (or internal auditory meatus) in the temporal bone.
Innervations[]
The vestibulocochlear nerve consists mostly of bipolar neurons and splits into two large divisions: the cochlear nerve and the vestibular nerve.
The cochlear nerve travels away from the cochlea of the inner ear where it starts as the spiral ganglia. Processes from the organ of Corti conduct afferent transmission to the spiral ganglia. It is the inner hair cells of the organ of Corti that are responsible for activation of afferent receptors in response to pressure waves reaching the basilar membrane through the transduction of sound. The exact mechanism by which sound is transmitted by the neurons of the cochlear nerve is uncertain; the two competing theories are place theory and temporal theory.
The vestibular nerve travels from the vestibular system of the inner ear. The vestibular ganglion houses the cell bodies of the bipolar neurons and extends processes to five sensory organs. Three of these are the cristae located in the ampullae of the semicircular canals. Hair cells of the cristae activate afferent receptors in response to rotational acceleration. The other two sensory organs supplied by the vestibular neurons are the maculae of the saccule and utricle. Hair cells of the maculae activate afferent receptors in response to linear acceleration.
Symptoms of damage[]
Damage to the vestibulocochlear nerve may cause the following symptoms:
- hearing loss
- vertigo
- false sense of motion
- loss of equilibrium (in dark places)
- nystagmus
- motion sickness
- gaze-evoked tinnitus.[2]
Name[]
Some older texts call the nerve the acoustic or auditory nerve [1], but these terms have fallen out of widespread use because they fail to recognize the nerve's role in the vestibular system. Vestibulocochlear nerve is therefore preferred by most.
See also[]
References[]
- ↑ Kolb, Bryan, and Ian Q. Whishaw. An Introduction to Brain and Behaviour. 2nd ed. New York City: Worth Publishers, 2011. 56-57. Print.
- ↑ (2001). Characteristics of patients with gaze-evoked tinnitus. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 22 (5): 650–4.
Additional images[]
External links[]
- MedEd at Loyola GrossAnatomy/h_n/cn/cn1/cn8.htm
- Norman/Georgetown cranialnerves (VIII)
- Notes on Vestibulocochlear Nerve
I-IV: olfactory - optic - oculomotor - trochlear
V: trigeminal: trigeminal ganglion
V1: ophthalmic: lacrimal - frontal (supratrochlear, supraorbital) - nasociliary (long root of ciliary, long ciliary, infratrochlear, posterior ethmoidal, anterior ethmoidal) - ciliary ganglion (short ciliary)
V2: maxillary: middle meningeal - in the pterygopalatine fossa (zygomatic, zygomaticotemporal, zygomaticofacial, sphenopalatine, posterior superior alveolar)
in the infraorbital canal/infraorbital nerve (middle superior alveolar, anterior superior alveolar)
on the face (inferior palpebral, external nasal, superior labial, infraorbital plexus) - pterygopalatine ganglion (deep petrosal, nerve of pterygoid canal)
branches of distribution (palatine, nasopalatine, pharyngeal)
V3: mandibular: nervus spinosus - medial pterygoid - anterior (masseteric, deep temporal, buccal, lateral pterygoid)
posterior (auriculotemporal, lingual, inferior alveolar, mylohyoid, mental) - otic ganglion - submandibular ganglion
VI: abducens
VII: facial: nervus intermedius - geniculate - inside facial canal (greater petrosal, nerve to the stapedius, chorda tympani)
at exit from stylomastoid foramen (posterior auricular, digastric - stylohyoid)
on face (temporal, zygomatic, buccal, mandibular, cervical)
VIII: vestibulocochlear: cochlear (striae medullares, lateral lemniscus) - vestibular
IX: glossopharyngeal: fasciculus solitarius - nucleus ambiguus - ganglia (superior, petrous) - tympanic - carotid sinus
X: vagus: ganglia (jugular, nodose) - Alderman's nerve - in the neck (pharyngeal branch, superior laryngeal ext and int, recurrent laryngeal)
in the thorax (pulmonary branches, esophageal plexus) - in the abdomen (gastric plexuses, celiac plexus, gastric plexus)
XI: accessory XII: hypoglossal
Auditory and vestibular pathways | ||||
---|---|---|---|---|
Auditory |
inner ear: Hair cells → Spiral ganglion → Cochlear nerve VIII → pons: Cochlear nuclei (Anterior, Dorsal) → Trapezoid body → Superior olivary nuclei → midbrain: Lateral lemniscus → Inferior colliculi → | |||
Vestibular |
inner ear: Vestibular nerve VIII → pons: Vestibular nuclei (Medial vestibular nucleus, Lateral vestibular nucleus) cerebellum: Flocculonodular lobe spinal cord: Vestibulospinal tract (Medial vestibulospinal tract, Lateral vestibulospinal tract) | |||
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