Cranial Nerves VIII and IX Flashcards
Is cranial nerve VIII motor or sensory?
Special sensory
Cranial nerve VIII is actually composed of what two nerves?
Vestibular and cochlear nerves
What is the nucleus of termination for the vestibular nerve?
Vestibular nuclear complex (superior, medial, lateral, and inferior)
What is the eponym for the superior vestibular nucleus?
Bechterew
What is the eponym for the medial vestibular nucleus?
Schwalbe
What is the eponym for the lateral vestibular nucleus?
Deiter
Where are the cell bodies for the vestibular nerve located?
Vestibular ganglion (superior and inferior parts)
Where is the vestibular ganglion located?
Internal acoustic meatus
What is the nucleus of termination for the cochlear nerve?
Cochlear nuclei (anterior and posterior parts)
Where are the cell bodies located for the cochlear nerve?
Spiral ganglion
What is the location of the spiral ganglion?
Within the cochlea
Peripheral processes (short dendrites) extend from the spiral ganglion to where first?
Spiral organ (organ of Corti)
Axons of the cochlear nerve terminate where?
On the two cochlear nuclei
From the cochlear nuclei, where do the axons synapse after they cross the brainstem and what is formed?
Trapezoid nuclei and lateral lemniscus is formed
From the lateral lemniscus, where will fibers travel to in the cochlear pathway?
Either the inferior colliculus or the medial geniculate body of the thalamus
What is the apparent origin of cranial nerve VIII?
Cerebellopontine recess/angle
Most vestibular nerve fibers of cranial nerve VIII terminate where?
In the medial vestibular nucleus (Schwalbe)
Some of the vestibular nerve fibers of cranial nerve VIII travel directly to the cerebellum by way of which peduncle?
Inferior cerebellar peduncle
The vestibulocochlear nerve travels through what area to the internal acoustic meatus where it enters along with the facial nerve?
Posterior cranial fossa
Which nerve of cranial nerve VIII contains more fibers?
Cochlear (30-40,000)
What branch of the vestibular nerve is larger?
Superior branch
What makes up the inferior branch of the vestibular nerve?
Saccular nerve and posterior ampullary nerve
What area of the ear is supplied by both the inferior and superior branches of the vestibular nerve?
Saccule
What forms the superior branch of the vestibular nerve?
Lateral and anterior ampullary nerves
What nerves supply the utricle?
Branch from the lateral ampullary nerve and a branch directly off the superior branch
What does Voit’s nerve supply?
Saccule (branch from the superior branch of the vestibular nerve)
What is a unilateral tumor of Schwann cells associated with cranial nerve VIII leading to hearing and equilibrium issues, as well as major headaches?
Acoustic neuroma
What is tinnitus?
Ringing sensation in the ears
Tinnitus could be a 1st sign of what condition?
Ménière’s disease
What kind of hearing loss do cochlear implants treat?
Sensorineural hearing loss