Now, as we see on the diagram, the membrane of these cells contains specialized proteins that are responsible for using ATP molecules, energy molecules, to establish a gradient inside our interstituum, between the interstituum and the inside the lumen of our loop of Henley. So let's discuss how this is actually achieved. So, let's begin on the basil lateral side of our cell. The basil lateral side of the cell is the side that points that faces our basement membrane, found in the interstituum of the surrounding thick loop of Henley. So this membrane contains sodium, potassium, Atpas pumps, and these utilize ATP molecules, energy molecules to basically move sodium ions against their electrochemical gradient. So three sodium ions are basically pumped from the inside of the cell to the outside of the cell.