The Bowman’s capsule extends into nephron tubule. There are four main tubules: the proximal convoluted tubule (PCT), the loop of Henle, the distal convoluted tubule (DCT) and the collecting tube. The tubules are the site for extensive re-absorption of useful plasma solutes. The useful solutes include: sugars and sodium; part of water is also reabsorbed back. This reabsorption is controlled by hormones. The main solute that is reabsorped back is sodium, whose reabsorption is important for the regulation of the concentration of salt in blood.