auditory and vestibular... from high yield neuro

Question 1

functional component of the AUDITORY system

Answer 1

Special Somatic Afferent

Question 2

embryonic origin of the AUDITORY system

Answer 2

ectoderm ==> otic placode ==> otic vesicle

Question 3

cheif sensory elements of the AUDITORY system

Answer 3

inner hair cells. these are 90% of the COCHLEAR nerve. they synapse on MYELINATED neurons

Question 4

role of outer hair cells?

Answer 4

modulate sound and reduce the threshold of inner hair cells

Question 5

how does sound info get to the cochlear nuclei?

Answer 5

• bipolar cells (cell bodies in spiral ganglion)
• project centrally as the cochlear nerve
• to cerebellopontine angle

Question 6

where do the cochlear nuclei send AUDITORY info?

Answer 6

DORSAL nucleus sends
- to CONTRALATERAL lateral lemniscus nucleus*** Dr. walker just calls it inferior colliculus

VENTRAL nucleus sends to

• BILATERAL superior olives,
• CONTRALATERAL lateral lemniscus nucleus,
• CONTRALATERAL inferior colliculus

Question 7

what is the trapezoid body?

Answer 7

it is the decussating fibers of the VENTRAL cochlear nuclei in the PONS

Question 8

lateral lemniscus receives info from ____ in the AUDITORY system

Answer 8

• CONTRALATERAL ventral cochlear nucleus
• CONTRALATERAL dorsal cochlear nucleus
• BILATERAL superior olivary nuclei
• the other lateral lemniscus

Question 9

where does MGN get AUDITORY info?

Answer 9

• nucleus of inferior colliculus (via its brachium)

- direct synapse from contralateral dorsal cochlear nucleus

Question 10

where does MGN info go?

Answer 10

• projects as AUDITORY RADIATION through internal capsule

- to primary auditory cortex: transverse temporal gyri of Heschel (areas 41,42)

Question 11

embryonic origin of the VESTIBULAR system

Answer 11

SAME AS AUDITORY :-)

ectoderm ==> otic placode ==> otic vesicle

Question 12

what is the crista ampularis

Answer 12

the thing that contains the hair cells

Question 13

where is linear accelleration/gravity detected?

Answer 13

in the SACCULE and UTRICLE

- hair cells that sense the movement of otoliths or endolymph

Question 14

I’m on a boat!! how do my hair cells transmit head position to the brainstem?

Answer 14

HAIR CELLS (of the semicircular ducts, saccule, utricle) are innervated by BIPOLAR cells (with cell bodies in vestibular ganglion) to project as the VESTIBULAR NERVE to the VESTIBULAR nuclei and FLOCCULONODULAR lobe of CBellum

Question 15

I wish I were a ballerina. If I were, I would be great at the vestibulooccular reflex. What exactly is that? What are the brainstem parts that it uses?

Answer 15

• allows you to fix your eyes on something while you spin.
• vestibular nuclei, MLF, occulomotor nuclei
• CN 3, 4, 6

Question 16

A dr. asks you to do a caloric nystagmus test on a comatose patient. What is that stupid mnemonic that helps you interpret the results?

Answer 16

COWS!!!
in a normal patient…..
Cold (makes nystagmus)Opposite; Warm (makes it) Same

Question 17

there is tonotopic orientation in projections from MGN to the superior temporal gyrus. what is a good metaphor for it?

Answer 17

Parents at a choir competition: LOW class parents (low tone) set up their camcorders on the anterolateral portion of the room. HIGH class parents (high tone) set up their camcorders in the posteromedial (back middle) and just zoom in.

Question 18

how does your brain link auditory receptive regions to motor speech areas?

Answer 18

the arcuate fasiculus!!