baryar
Forum Newbie
Topics: 6
Posts: 26
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resting mebrane potential is -90mV,
sodium equilibrium potential is +45mV,
so net force on sodium is 135mV,directed to inward of cells.
sodium channels are closed in resting conditions of the cells,but still this large inward force causes a sodium ion leak into the cell and it is passive.
whats the mechanism of this sodium leak into the cells when aal sodium channels are closed.is there some other route as well for inward passive transport of sodium?
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| baryar
Forum Newbie
Topics: 6
Posts: 26
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so no one really bothers to share his/her knowledge regarding the topic?
come'on fellows
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| mildus
Forum Guru
Topics: 19
Posts: 614
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"Whats the mechanism of this sodium leak into the cells when all sodium channels are closed.is there some other route as well for inward passive transport of sodium?"
There are two kinds of channels:
1. passive channels or leaky channels (they are always open!)
2. active channels or gated channels
-a) voltage gated
-b) ligand gated
So, sodium goes into the cell through its channels which are always open, but this is not much. That sodium contributes to the membrane potential (the reason why membrane potential isn't the same as equilibrium potential for potassium, but slightly less negative).
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| baryar
Forum Newbie
Topics: 6
Posts: 26
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u r very right,thats xactly wat i found in my research and discussions.
but still there remains a bit ambiguity and i m still confused.bcaz the un-gated (or what u call leaky) channels are found in some epithelial cells only.aal cells dont have these un-gated (always-open) sodium channels.these are only found in some epithelial cell.
but i think u gave the answer for to my question.ur answer is xactly wat i was looking forwards to
KEEP SMILING
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