The same thing is true for these other two. But for potassium, they will move in the opposite, because potassium has a higher concentration on the inside than on the outside. Now, when the cell is resting, our sodium as well as the calcium voltage gated channels are closed, but the potassium is able to actually leak into this or actually outside of the cell. And because our potassium can leak slightly to the outside of the cell, that's exactly why our membrane is negative on the inside than on the outside, because we have a leakage of these potassium to the outside. And that basically creates a slightly negative membrane potential on the inside of the cell. So phase four is the resting membrane potential.