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 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. 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...