And aquaporeans are these specialized types of channels found on the apical side of our membrane that are responsible for actually allowing the movement of water across the membrane. Now, the question is, in what direction will the water actually flow? Will the water flow out of the filtered and into the interstituum, or from the interstituum and back into our lumen of the collecting dug? Well, the answer lies in the following idea. Recall what the function of the loop of Henley was in our discussion on the countercurrent multiplier system and the loop of Henley. We basically said that what the loop of Henley does is it creates a high concentration of ions of solute ions in the interstituum of aramidoula.