Now, notice we have many more of these red dots on the outside than on the inside, and many more of these purple dots on the inside than on the outside. So that implies that when the membrane is resting, when it is not generating any action potential, we have many more sodium ions on the outside than on the inside. And conversely, we have many more potassium on the inside than on the outside. And this table describes what the concentrations are. So for sodium on the inside, we have 15 millimolar. And for the outside, we have 150 millimolar.