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  • The vestibulocochlear nerve, known as the eighth cranial nerve, transmits

  • sound and equilibrium information from the inner ear to the brain.

  • Structure 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 in the utricle activate

  • afferent receptors in response to linear acceleration while hair cells of the

  • maculae in the saccule respond to vertically directed linear force.

  • = Development = The vestibulocochlear nerve is derived

  • from the embryonic otic placode. Function

  • This is the nerve along which the sensory 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 in the temporal bone.

  • The vestibulocochlear nerve carries axons of type SSA, special somatic

  • afferent, which carry the modalities of hearing and equilibrium.

  • Clinical significance = Symptoms of damage =

  • Damage to the vestibulocochlear nerve may cause the following symptoms:

  • hearing loss vertigo

  • false sense of motion loss of equilibrium

  • nystagmus motion sickness

  • gaze-evoked tinnitus. = Examination =

  • History = Etymology =

  • Some older texts call the nerve the acoustic or auditory nerve, 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

  • Auditory system References

  • Additional images External links

  • MedEd at Loyola GrossAnatomycncn8.htm cranialnerves at The Anatomy Lesson by

  • Wesley Norman Notes on Vestibulocochlear Nerve

The vestibulocochlear nerve, known as the eighth cranial nerve, transmits

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