Electrochemical gradients

[Simfish]

Or, the combination of a chemical gradient and an electric gradient.

So suppose you have a postsynaptic membrane. The postsynaptic space is negatively charged, but it also has a huge number of Na+ ions relative to the extracellular space. So if you open up a channel, the electrical gradient is going to try to keep the Na+ inside. But the chemical gradient is going to drive some Na+ ions outside.

Does the chemical gradient simply act on the laws of diffusion/mere probability? Probability meaning that there are *far* more configurations with equal amounts of Na+ ions on both sides than one side having almost all of the Na+ ions?

And because of this, is the electrical gradient intrinsically "faster" than the chemical gradient? Diffusion is slow. But electric repulsion/attraction is very fast.

 

[FlyingPanda]

Don't quote me on this, as it is just my own ideas, but yes I think it is simply a case of two opposing forces acting in different directions, and one being simply stronger than another. It's like two vehicles pulling the same load in opposite directions, except one vehicle is a truck, and the other is a motorcycle.