exam 2 vestibulocochlear Flashcards
what type of signal is transmitted by the vestibulocochlear nerve?
it is purely a sensory nerve
what is the vestibulocochlear nerve composed of?
two nerves
the vestibular nerve
the cochlear nerve
where does the vestibular nerve terminate?
vestibular nuclear complex -consists of four parts superior inferior medial lateral
what does the vestibular nuclear complex consist of?
it consists of four parts superior inferior lateral medial
fibers carried in the vestibular nerve arise from cell bodies located where?
vestibular ganglion
the vestibular ganglion consists of what parts and is located where?
inferior and superior parts and is located in the internal acoustic meatus
what do the fibers of the vestibular nerve arise from?
cell bodies in the vestibular ganglion
where does the cochlear nerve terminate?
two cochlear nuclei
anterior cochlear nuclei
posterior cochlear nuclei
what is the cochlear nerve composed of?
axons from the spiral ganglion
-located in the cochlear
the cochlear nerve is made up of what type of neurons, and where are their cell bodies located?
it is made up of BIPOLAR neurons with cell bodies located in the spiral ganglion of the cochlea
peripheral processes of the cochlear nerve extend from where to where?
the peripheral processes extend from the spiral ganglion to the spiral organ (organ of corti)
axons from the cell bodies of the spiral ganglion are carried in the cochlear nerve to terminate on what nuclei? located where?
the anterior and posterior cochlear (two nuclei)
located in the posterior, superior medulla oblongata lateral to the vestibular nuclei
continuing with the auditory pathway, axons extend from the cochlear nuclei and do what?
they cross to the other side of the brainstem and synapse in the trapezoid nuclei
continuing with the auditory pathway, axons extend from the trapezoid nuclei and do what?
form the lateral lemniscus
peripheral processes from the vestibular ganglion extend to what?
the peripheral processes extend to three inner ear structures.
the saccule
the utricle
the semicircular canals
central process from the vestibular ganglion conveys information to what nuclei? located where?
the vestibular nuclei
located in the medulla oblongata on the floor of the rhomboid fossa
most vestibular nerve fibers will terminate where?
the medial vestibular nucleus (schwalbe)
while most vestibular nerve fibers will terminate in the medial vestibular nucleus (schwalbe), some fibers will travel where?
they will travel directly to the cerebellum by way of the inferior cerebellar peduncle
what is the apparent origin of the vestibular nerve?
cerebellopontine angle
the vestibular nerve travels through which cranial fossa on its way to the internal acoustic meatus?
the posterior cranial fossa
what enters the the internal acoustic meatus with the vestibular nerve?
the facial nerve
how many fibers does the cochlear nerve carry with in the temporal bone?
30-40,000 fibers
god damn…
within the temporal bone the cochlear nerve transverses the internal acoustic meatus inferior to what?
inferior to the facial nerve
after the cochlear nerve exits the temporal bone, what does it reach?
the spiral gangion of the cochlea
after exiting the temporal bone how many fibers does the vestibular nerve carry?
20,000
as the vestibular nerve approaches the ear, what does it do?
divides into superior and inferior branches
what is the fiber distribution for the inferior and superior branches of the vestibular nerve as it approaches the ear?
superior is 12,000 LARGER
inferior is 8,000 smaller
the inferior branch of the vestibular nerve is composed of what nerves?
saccular nerve
posterior ampullary nerve
which surprisingly supply the saccule and posterior ampullary crest
the superior branch of the vestibular nerve is composed of what nerves?
lateral and anterior ampullary nerve
which supplies the lateral and anterior semicircular canals
what supplies the anterior and lateral semicircular canals?
the lateral and anterior ampullary nerves of the superior branch of the vestibular nerve
how is the utricle innervated?
supplied by a branch of the lateral ampullary nerve, and a branch directly off of the superior branch of vestibular nerve
how is the saccule innervated?
a branch directly from the superior branch of vestibular nerve. (Voit’s nerve)
what are the clinical considerations related to cranial nerve 8?
acoustic neuroma
tinnitus
cochlear implants
vestibular disease
