So once again, ADH stimulates the epithelial cells to produce membrane protein channels known as aquaphorns. These channels allow the passive transport of water down its gradient to the outside to our interstituent from the filtrate found in the lumen of the collecting duct. And this is because of the fact that the loop of Henley established this electrochemical gradient. It concentrated the interstitium so that there is a higher concentration, a higher hypertonicity in the outside than on the inside. Now, the next question is what exactly is the function of aldosterone? So we saw that ADH is responsible for producing these aquaporums, and we'll discuss that in more detail in just a moment.