The only place we actually use energy is in the thick ascending loop of Henley. So within the thick ascending loop of Henley, we establish an electrochemical gradient by using ATP. And then in the descending loop of Henley, we utilize that electrochemical gradient to passively move water out of our tubial. And as a result of all that water moving out of our tubule, we concentrate our filtrate towards the bottom of the loop of Henley. And that's exactly why, in the thin, ascending loop of Henley, the sodium and chloride even further move to the outside, concentrating the outside even more. So this is a function of the lupus Henley.