CN VIII Flashcards
What CN is the vestibulocochlear Nerve?
CN VIII
What kind of nerve is the vestibulocochlear nerve?
Sensory only
How many nerves make up the vestibulocochlear nerve?
2
What two nerves make up the vestibulocochlear nerve?
Vestibular nerve
Cochlear nerve
What does the vestibulocochlear nerve deal with?
Hearing and equilibrium
Where does the vestibular never terminate?
Vestibular nuclear complex
What are the four parts making up the vestibular nuclear complex?
Superior
Medial
Lateral
Inferior
What is another name for the superior part of the vestibular nuclear complex?
Bechterew
What is another name for the medial part of the vestibular nuclear complex?
Schwalbe
What is another name for the lateral part of the vestibular nuclear complex?
Deiter
What cell bodies are found in the lateral (Deiter) part of the vestibular nuclear complex?
Cell bodies of the vestibulospinal fibers
Where do fibers carried in the vestibular nerve arise from?
Cell bodies in the vestibular ganglion
What are the parts of the vestibular ganglion?
Superior and inferior parts
How many cochlear nuclei are there?
Anterior and posterior
Where does the cochlear nerve terminate?
In the two cochlear nuclei
Where are the cochlear nerve fibers cell bodies?
In the spiral ganglion of cochlea
What is the cochlear nerve made of?
Bipolar neurons
Where do the cochlear dendrites travel?
From spiral ganglia to spiral organ (organ of corti)
What is the spiral organ of Corti?
Receptor for hearing
How do the cochlear neurons travel?
Axons from the organ of corti carried in the cochlear nerve to the two vestibular nuclei
Where are the cochlear nuclei found?
Posterior, superior medulla oblongata, lateral to the vestibular nuclei
How do the cochlear axons travel from the cochlear nuclei to the trapezoid nuclei?
Axons cross to other side of brain stem synapse, form the lateral lemniscus
How does the lateral lemniscus travel?
Ascending info
Where do dendrites from the vestibular ganglion extend to?
Saccule
Utricle
Semicircular canals
Where do axons from the vestibular ganglion send info to?
Vestibular nuclei in MO
Where is the vestibular nuclei found?
In the medulla oblongata on the floor of the rhomboid fossa
Where do most vestibular nerve fibers synapse?
Medial (schwalbe) vestibular nucleus
Where will some of the vestibular nerve fibers terminate?
Directly to cerebellum via inferior cerebellar peduncle
Floccunodularlobe
How does the info from the vestibulocochlear nerve travel?
Distal to proximal
What is the apparent origin of the vestibulocochlear nerve?
Cerebellarpontine angle
How does the vestibulocochlear nerve travel?
In posterior cranial fossa to the internal acoustic meatus
What other nerve does the vestibulocochlear nerve enter the internal acoustic meatus with?
Facial nerve
What bone does the vestibulocochlear nerve travel in?
Temporal bone
Who many fibers does the cochlear nerve carry? **
30,000-40,000
How does the cochlear nerve travel in the temporal bone?
Transverses the internal acoustic meatus inferior to the facial nerve
Leaves and reaches the spiral ganglion of cochlea
How many fibers does the vestibular nerve carry?
20,000
What does the vestibular nerve divide into?
Superior and inferior branches as it approaches the ear
Which branch of the vestibular nerve is smaller?
Inferior branch
How many fibers does the inferior vestibular never carry?
8,000
What nerves make up the inferior branch of the vestibular nerve?
Saccular nerve
Posterior ampullary nerve
What does the saccular nerve supply?
The saccule
What does the posterior ampullary nerve supply?
The posterior ampullary crest
How many fibers make up the superior vestibular branch?
12,000
What nerves make up the superior vestibular branch?
Lateral ampullary nerve
Anterior ampullary nerve
What do the lateral and anterior ampullary nerves supply?
Lateral and anterior semicircular canals
What is the utricle supplied by?
A branch from the lateral ampullary nerve and a branch off of the superior vestibular branch
What is Voit’s nerve?
Branch directly off the superior vestibular branch supplying the saccule
What is the saccule supplied by?
Voit’s nerve
What is an acoustic neuroma?
Tumor (vestibular schwanoma)
Can be sizable
Only affects one side
Hearing and equilibrium problems
What is tinnitus?
Ringing ears
What are cochlear implants?
Helps with sensorineural hearing loss
Hot topic in deaf community
What is vestibular disease?
Results in vertigo (spinning feeling)
How is vestibular disease different than cervicogenic vertigo?
Cervicogenic vertigo you can produce by placing the patient on a spinning chair and slightly moving it
What is the name of CN VIII?
Vestibulocochlear nerve
