Now, the second function of the Proximal Convoluted tubule is that in secretion, it secretes certain types of molecules and ions that are no longer needed by our body. And this includes things like hydrogen ions as well as bicarbonate ions, as we'll see in just a moment. Now, the final function of our Proximal Convoluted tubule is to actually prevent the movement of waste products from the filtrat found inside the lumen of the Proximal convolute and into our blood system. So the Proximal convolute not only reabsorbs and secretes molecules and ions, but it also prevents the movement of waste products from actually returning and moving back into our blood plasma, such as, for example, urea. Now, if we zoom in on any section of the Proximal Convoluted tubule, if we examine the inner lining of that tubule, we're going to see epithelial cells. So the inner wall lining of the Proximal Convoluted tubule contains many of these epithelial cells that are connected by special types of junctions known as tide junctions.