Now, the distal convoluted tubule is a portion of the nephron that reabsorbs some of the sodium as well as our calcium, while at the same time secreting potassium as well as the hydrogen ions into our filtrate. Now, in the presence of certain hormones, such as the antiduretic hormone ADH, this becomes permeable to water, and it reabsorbs the water from that filtrate back into our blood plasma. Finally we have this section known as the Collecting duct. And the collecting duct is found in the medulla portion of our kidneys. Just like the vase erecta and our loop of Henley. Now the collecting duct is permeable to sodium.