Can someone corroborate (sp?) this or correct it?

[Knicks]

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Hey, just don't want to take any chances at this point and so I want to ask you guys to affirm if the following is true (please read carefully):

The resting membrane potential is negative (-70) because there's an excess of positive ions outside the cell and an excess of negative ions inside the cell. K+ efflux/leak through the un-gated K+ channels maintains the negative charge inside the membrane, which approaches the equilibrium potential for K+.

However,, a small number of channels allow Na+ influx, and this small influx of Na+ increases the membrane potential (makes it more positive). And for this reason, the resting membrane potential is always less negative (more positive) than the equilibrium potential for K+.

Conclusion: The resting membrane potential is due to high potassium conductance AND a little bit of sodium conductance.

 

[biotsrama]

All looks pretty good to me! 🙂

 

[str8flexed]

What messes with my mind, is that I know the gradient of K+ is maintained by the balance between K+ concentration inside and out of the cell, as well as charge. But where does the Na+/K+ pump come into play? If you only account for those 2 factors, you're forgetting 2 K+'s are being pumped into the cell..

I guess the equillibrium takes into account the concentration, electrical charge, AND the pump constantly pumping K+ into the cell.

 

[McGillGrad]

Yap...so when you get a questions about what is most responsible for depolarization it is the activation of K channels, not Na channels.