MathBench > Cellular Processes

Nernst Potential


Permeability is Key

So there are two opposing gradients affecting membranes: one for concentration, and one for voltage. But, and this is a big BUT:

The gradients only have an effect IF ions can move through the membrane. If you put a brick wall between in place of the membrane, you could have all sorts of differences in concentration and voltage, but those differences won't have any effect in the real world. And a membrane with no open channels is actually a lot like a brick wall.


closed channels:   open channels:
closed channels   open channels


We'll see how this plays out in the equations soon...