Lecture 43 4/29/24 Flashcards

1
Q

What is the function of the stria vasculare?

A

makes the endolymph for the cochlea

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2
Q

What are the characteristics of the organ of Corti?

A

-sits on basilar membrane
-hairs come up to tectorial membrane

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3
Q

Which structures are present within the cochlea?

A

-scala vestibuli
-scala media
-scala tympani
-tectorial membrane
-basilar membrane
-vestibular membrane
-organ of Corti

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4
Q

What happens in the organ of Corti that allows for louder sounds to be perceived?

A

-higher amplitude sound wave causes more movement of the basilar membrane
-increased basilar membrane movement triggers more hair cells
-the more hair cells triggered, the louder the noise

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5
Q

What are the characteristics of the basilar membrane near the oval window?

A

-“base”
-narrow
-stiff
-greater movement with high frequency sound waves

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6
Q

What are the characteristics of the basilar membrane far from the oval window?

A

-“apex”
-wide
-flexible
-greater movement with low frequency sound waves

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7
Q

What is tonotopic organization?

A

-brain can tell where along the basilar membrane the triggered hair cells are located
-helps with determining high vs low frequency

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8
Q

What is the role of the spiral ganglion?

A

receive input from the tectorial membrane and transmit it to the brain

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9
Q

What is the relationship between number of coils in the cochlea and the range of sounds heard?

A

the greater the number of coils, the greater the range of frequencies heard

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10
Q

How does ear position impact ability to hear sound?

A

ears that are closer together on the skull are able to hear higher frequency sounds

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11
Q

What are the potential diseases of the inner ear?

A

-labyrinthitis/otitis interna
-noise-induced degeneration
-age-induced degeneration
-chemical degeneration
-cochlear dysgenesis/agenesis

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12
Q

What is sensorineural deafness?

A

deafness due to the inability of the inner ear to process sound

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13
Q

What can cause sensorineural deafness?

A

-disease of inner ear
-congenital problems of inner ear

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14
Q

How does treatment differ between degeneration disease and genetic cochlear disease?

A

-degeneration disease treated with hearing aids
-genetic cochlear disease treated with cochlear implant

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15
Q

What is the auditory cortex?

A

part of the cerebral cortex where the conscious perception of sound occurs

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16
Q

How is sound processed in the brain, based on which ear heard it?

A

-left auditory cortex processes sound heard in right ear, and vice versa

17
Q

Why is hearing considered a learned response?

A

the temporal lobe learns patterns of sounds

18
Q

What are the characteristics of albinotic deafness?

A

-associated with decreased pigmentation
-due to failure of neural crest cell migration; lack of stria vasculare
-unable to produce endolymph in cochlea

19
Q

What are the characteristics of abiotrophic deafness?

A

-spontaneous death of sensory hair cells after normal development
-later onset than albinotic deafness
-super rare form

20
Q

How can hearing be assessed?

A

-physical exam
-behavioral responses
-electrodiagnostics

21
Q

How is the inner ear formed?

A

invagination of ectoderm to form the otic vesicle, which becomes the inner ear

22
Q

Which type of embryologic tissue forms the tympanic cavity?

A

endoderm

23
Q

Which type of embryologic tissue forms the middle ear ossicles?

A

mesoderm

24
Q

Which type of embryologic tissue forms the external ear canal?

A

ectoderm

25
Q

How does the cochlea work?

A

-sound waves first move through the scala vestibuli
-turn around and move through scala tympani
-sound waves in scala tympani are able to move the basilar membrane and activate organ of Corti
-hair cells in the organ of Corti come up to the tectorial membrane and can transmit to the membrane when sound waves cause movement in the hair cells