Flashcards in Cochlear Electrophysiology Deck (14):
Scala media is filled with what kind of liquid? What is the voltage of the liquid?
-Endolymph, +80 mV
Scala vestibuli is filled with what kind of liquid? What is the voltage of the liquid?
-Perilymph, 0 mv
Scala tympani is filled with what kind of liquid? What is the voltage of the liquid?
-Perilymph, 0 mV
What is the resting voltage of the outer and inner hair cells?
-OHCs: -70 mV
-IHCs: -45 mV
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
What is the source of the endocochlear potential? What types of cells help generate it?
-Ion pumps of the stereocilia
Where are the ion channels on the stereocilia?
-In the tip-links at the superior-most portion of the stereocilia
Stereocilia must be fast enough to do what?
-Facilitate fast enough ion transfer for high frequencies
What are the cochlear potentials? Which respond to stimuli?
-Compound action potential
-Active potentials respond to stimuli
Which potential mimics the stimulus fine structure? Is it more like AC or DC?
Which potential mimics the stimulus envelope? Is it more like AC or DC?
Where is the compound action potential generated?
-Spiral ganglion of the ANFs
What goes up to higher frequencies, the cochlear microphonic or the inner hair cell potential?