nov19pt1 Flashcards
endolymph bathes the ___ side
apical
emdolpym has this potential relative to perilymph
positive 80
potential diff between endolymph and inside IHC
125
RMP inside IHC
negative 60 to negative 45
what brings K+ into IHC
ELECTRICAL driving force, despite lack of chemical gradient
potassium flows in from endolymph, producing depol so that ___ open
voltage gated Ca
IHC NT
glutamate
post syn of IHC receptors located
auditory nerve endings
why some IHC have RMP at negative 45
constitutively open potassium channels
proteins that form tip links
cadherin 23 and protocadherin 15
supporting evidence for tip links being needed in mechantotransduction
calcium chelators stop mechanotransduction (by causing proteins of tip links to dissociate)
spatial sensitivity of response of IHC
0.3nm
time frame of mechantsduction response in IHC
les than 10 microseconds
percent constitutivley open
about 15
potassium channels open when ___ is pushed toward ____
short, tall stereocilium
little respond if pushed
perpendicular
degree of depol depends on
displacement of stereocilium
depolarization is ___ to ___
short against tall (open potassium channel)
depolarization direction is called the ___ direction
positive
Lateral inhibition means
desensitize neighboring receports to sharpen response
basilar membrane at base of cochlea repsonds better to
high frequencies
at 0cm, basilar membrane responds to 20thousand Hz means at 1 cm away, responds at
2 thousand Hz (logarithmic scale)
tuning curve of hair cells depends on
location on basilar membrane and type of channels they have
two broad categories of deafness
problems with middle ear bones or problem with tip links
