I will show you that the movement of ions across the cell membrane in a neuron cell is identical to the movement of ions in a concentration cell. And in fact, a neuron cell is a more complex version of a concentration cell. So let's begin. So let's this is our cell membrane in a neuron cell. Here's our outside, the cell and the inside of the cell. Now, assuming our cell reaches a rusting electrical potential, we're going to have many more of these sodium ions on the outside than on the inside.