Cochlear Electrophysiology Flashcards Preview

HESP634 > Cochlear Electrophysiology > Flashcards

Flashcards in Cochlear Electrophysiology Deck (14):
1

Scala media is filled with what kind of liquid? What is the voltage of the liquid?

-Endolymph, +80 mV

2

Scala vestibuli is filled with what kind of liquid? What is the voltage of the liquid?

-Perilymph, 0 mv

3

Scala tympani is filled with what kind of liquid? What is the voltage of the liquid?

-Perilymph, 0 mV

4

What is the resting voltage of the outer and inner hair cells?

-OHCs: -70 mV
-IHCs: -45 mV

5

Why is it important to have a potential difference across scala media and hair cells?

-125-150 mV potential difference between the endolymph and inside of the HCs creates a large voltage gradient, which drives K+ ions into the cell when ion channels are open
-In accordance with the Davis Battery Theory

6

What is the source of the endocochlear potential? What types of cells help generate it?

-Ion pumps of the stereocilia

7

Where are the ion channels on the stereocilia?

-In the tip-links at the superior-most portion of the stereocilia

8

Stereocilia must be fast enough to do what?

-Facilitate fast enough ion transfer for high frequencies

9

What are the cochlear potentials? Which respond to stimuli?

-Resting potential:
-Endocochlear potential
-Intracellular potential
-Active potentials:
-Cochlear microphonic
-Summating potential
-Compound action potential

-Active potentials respond to stimuli

10

Which potential mimics the stimulus fine structure? Is it more like AC or DC?

-CM
-AC

11

Which potential mimics the stimulus envelope? Is it more like AC or DC?

-SP
-DC

12

Where is the compound action potential generated?

-Spiral ganglion of the ANFs

13

What goes up to higher frequencies, the cochlear microphonic or the inner hair cell potential?

-CM

14

What cells produce OAEs?

-OHCs