Auditory and Vestibular Pathways - Fitz/Mic

Question 1

Identify the location of the cell bodies that are A) afferent from and 2) efferent to the cochlea

Answer 1

A) spiral ganglion B) superior olivary complex

Question 2

Name the 3 main motor efferents coming out of the olivary nucleus in the auditory pathway:

Answer 2

Connect to outer hair cells through the olivocochlear bundle

Connect to tensor tympani muscle through the trigeminal nerve (5)

Connect to stapedius through facial nerve (7)

Question 3

Weber results in conductive vs sensorinerual loss?

Answer 3

Conductive Loss
-louder in affected ear

Sensorineural Loss
-will be louder in unaffected ear

How does that work for the conductive one? Because in the conductive test, the unaffected ear is subject to all of the environmental outside noise. Therefore the sound will be louder on the affected side that is basically only receiving bone conduction

Question 4

Trace the auditory pathway!

From Hair cells to the primary auditory cortex

Answer 4

• Hair Cells to spiral ganglion
• Spiral ganglion to cochlear nucleus through CN 8
• Cochlear nucleus to superior olivary complex through the trapezoid
• Sup. Olivary Nucleus to Inf. Colliculus thru Lateral Lemniscus
• Inf. Colliculus to Med. Geniculate Nucleus thru the brachium
• Med. Geniculate Nucleus to Primary Auditory Cortex thru internal capsule

Question 5

An comes in with a lesion and can no longer hear in one ear!

Possible locations of the damage?

Answer 5

If it is a single lesion, they must have a peripheral defect

At the cochlea, auditory nerve, or cochlear nucleus

Question 6

If someone has bilateral hearing loss from a single lesion, where must the lesion be?

Answer 6

Central!

Question 7

How will electrically stimulating neurons in the superior olivary complex affect otoacoustic emmisions?

Answer 7

Stimulating the Sup. Oliv. Complex will decrease the contraction of outer hair cells and result in a decrease in otoacoustic emissions!

Question 8

How will electrically stimulating neurons in the superior olivary complex affect the transmission of low frequency sounds to the cochlea?

Answer 8

Stimulating the Sup. Oliv. Complex will cause contraction of the tensor tympani muscle, resulting in decreased transmission of low frequency sounds to the cochlea

Question 9

What are the 4 different endpoints of the vestibular system?

Answer 9

1-vestibular cortex
2-Vestibulo-Ocular Reflex (MLF)
3-Vestibulospinal Reflexes (VST)
4-Vestibulocerebellar reflexes (flocculonodular lobe)

Question 10

What connects the inferior colliculus to the medial geniculate nucleus?

Answer 10

The brachium of the inferior colliculus

Question 11

What structures are separated by fibres of the facial nerve?

NOT ON TEST

Answer 11

Superior vestibular nucleus
and
abducens nucleus