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#1
09-12-2012
 USMLE Forums Newbie Steps History: Not yet Posts: 8 Threads: 7 Thanked 4 Times in 2 Posts Reputation: 14
help me with membrane potential.

In the resting cell, let's say membrane potential is -70mV. And I know the concentration of
Na+ inside the cell is lower than that of outside. When I apply Goldman equation to this,

something's bothering me. When Na+ channel is open, the permeability of Na+ will increase

and then many Na+ will go into the inside of cell. And I think the concentration of Na+in

side the cell will be increasing and that of outside of the cell will be decreasing. If

then, i think when we apply Goldman equation to that situation, we should change not only

the value of Permeability but also the concetration of Na+ inside and outside of the cell.

But we take only the value of Permeability into consideration. I don't understand why. And is there any good article for me to study membrane potential?

thank you

#2
03-18-2014
 USMLE Forums Scout Steps History: Step 1 Only Posts: 19 Threads: 5 Thanked 10 Times in 4 Posts Reputation: 20

Quote:
 Originally Posted by Dry815 Question about membrene potential. In the resting cell, let's say membrane potential is -70mV. And I know the concentration of Na+ inside the cell is lower than that of outside. When I apply Goldman equation to this, something's bothering me. When Na+ channel is open, the permeability of Na+ will increase and then many Na+ will go into the inside of cell. And I think the concentration of Na+in side the cell will be increasing and that of outside of the cell will be decreasing. If then, i think when we apply Goldman equation to that situation, we should change not only the value of Permeability but also the concetration of Na+ inside and outside of the cell. But we take only the value of Permeability into consideration. I don't understand why. And is there any good article for me to study membrane potential? thank you
its because the extracellular sodium being really high than the intracellular sodium,even when the Na+ chnnels are kept open,the change in extracellular sodium is negligible,and so it is not considered

 Tags Cell-Biology-, Physiology-

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