4 Auditory System

Question 1

Describe the pathway of a sound wave from the footplate of the stapes to the round window.

Answer 1

..

Question 2

What window the footplate of the stapes lays in?

Answer 2

Oval window!

Oval window of the membranous labyrinth of the inner ear

Question 3

Why do we lose high-tone hearing first?

Answer 3

With aging, our basilar membrane stiffen beginning at the base, hence we first lose high pitched tones first

Question 4

What is scala media filled with?

Answer 4

Endolymph

Question 5

What is the predominant positively charged ion in the endolymph?

Answer 5

K+ potassium

Question 6

Upon movement of the basilar membrane the hair cells stereocillia will touch what structure?

Answer 6

Tectorial membrane

Question 7

Where does stria vascularis reside?

Answer 7

In cochlea: Scala media

Question 8

What part of the basilar membrane does the sound wave reach first?

Answer 8

Base

Base —–> apex

Organ or corti

Question 9

Which part of the basilar membrane resonate with high frequency wave lengths? Why?

Answer 9

BASE!!!

Much more narrow

Question 10

Where is the spiral ganglion located?

Answer 10

Around the bony modiolus where the cochlear duct turns

Question 11

Which is the main auditory nucleus of the midbrain?

Answer 11

Medial geniculate nucleus

Question 12

Which is the main auditory nucleus of the thalamus?

Answer 12

Medial geniculate nucleus

Question 13

Where is the primary auditory cortex?

Answer 13

First (anterior) transverse temporal gyrus but may extend into second (posterior) gyrus too

Question 14

Injury of the cochlear nerve will result in ________ deafness.

Answer 14

Sensorineural deafness

CN 8 vestibulocochlear tumor

Question 15

Injury of the stapes will result in ____________ deafness.

Answer 15

Conductive deafness!

Question 16

Where is the spiral ganglion located?

Answer 16

Around the bony modiolus where the cochlear duct turns

Question 17

If your patient can hear the tuning fork longer in front of their pinna than when it is touching the mastoid process what
does this mean to you?

Answer 17

Normal hearing

Question 18

If your patient hears the tuning fork, when placed on the sagittal suture of the skull better with their left ear what has
happened with their bone conductance to the right?

Answer 18

Bone conductance still equal. Damage prevents patient from hearing the fork on right side

Question 19

What hearing test is based on bone conductance only?

Answer 19

Webber test!

Only Webber

Question 20

What does “lateralizing to the left” mean?

Answer 20

The bone conductance is equal, but the auditory nerve damage prevents the patient from hearing the fork vibration on the affected side

Question 21

Can you think of a scenario where there will be lateralization to the right on Weber test and the right Rinne test is abnormal?

Answer 21

…wut

Question 22

What kind of hearing loss will cause a tumor of the auditory nerve?

Answer 22

Sensorineural deafness

‘Sense a tumor’

Question 23

What kind of hearing loss will cause a fracture of the base of the skull affecting the inner auditory meatus? What if the
fracture is in the middle ear?

Answer 23

SENSORINEURAL DEAFNESS Tumor here will cause bone fracture of skull!

Fractures around the ear itself, will be most likely CONDUCTIVE DEAFNESS