4 Auditory System Flashcards
Describe the pathway of a sound wave from the footplate of the stapes to the round window.
..
What window the footplate of the stapes lays in?
Oval window!
Oval window of the membranous labyrinth of the inner ear
Why do we lose high-tone hearing first?
With aging, our basilar membrane stiffen beginning at the base, hence we first lose high pitched tones first
What is scala media filled with?
Endolymph
What is the predominant positively charged ion in the endolymph?
K+ potassium
Upon movement of the basilar membrane the hair cells stereocillia will touch what structure?
Tectorial membrane
Where does stria vascularis reside?
In cochlea: Scala media
What part of the basilar membrane does the sound wave reach first?
Base
Base —–> apex
Organ or corti
Which part of the basilar membrane resonate with high frequency wave lengths? Why?
BASE!!!
Much more narrow
Where is the spiral ganglion located?
Around the bony modiolus where the cochlear duct turns
Which is the main auditory nucleus of the midbrain?
Medial geniculate nucleus
Which is the main auditory nucleus of the thalamus?
Medial geniculate nucleus
Where is the primary auditory cortex?
First (anterior) transverse temporal gyrus but may extend into second (posterior) gyrus too
Injury of the cochlear nerve will result in ________ deafness.
Sensorineural deafness
CN 8 vestibulocochlear tumor
Injury of the stapes will result in ____________ deafness.
Conductive deafness!
Where is the spiral ganglion located?
Around the bony modiolus where the cochlear duct turns
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?
Normal hearing
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?
Bone conductance still equal. Damage prevents patient from hearing the fork on right side
What hearing test is based on bone conductance only?
Webber test!
Only Webber
What does “lateralizing to the left” mean?
The bone conductance is equal, but the auditory nerve damage prevents the patient from hearing the fork vibration on the affected side
Can you think of a scenario where there will be lateralization to the right on Weber test and the right Rinne test is abnormal?
…wut
What kind of hearing loss will cause a tumor of the auditory nerve?
Sensorineural deafness
‘Sense a tumor’
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?
SENSORINEURAL DEAFNESS Tumor here will cause bone fracture of skull!
Fractures around the ear itself, will be most likely CONDUCTIVE DEAFNESS
