Tere are about one million nephrons in the cortex of each kidney, and each one consists of a renal corpuscle and a renal tubule which carry out the functions of the nephron. The renal tubule consists of the proximal convoluted tubule, the loop of Heinle, and distal convoluted tubule.
The nephron is part of the homeostatic mechanism of your body. This system helps regulate the amount of water, salts, glucose, urea and other minerals in your body. The nephron is a filtration system located in your kidney that is responsible for the reaborption of water, salts. This is where glucose eventually is absorbed in your body. One side note, diabetics have trouble reaborbing the glucose in their body and hence a lot of it comes out in the urine - hence the name "diabetic" or "sweet urine."
The Loop of Henle is the part of the nephron that contains the basic pathway for liquid. The liquid begins at the Bowman's capsule (upper left) and then flows through the proximal convoluted tubule (that mess of tangled stuff up top). It is here that Sodium, water, amino acids, and glucose get reabsorbed. The filtrate then flows down the descending limb and then back up. On the way it passes a major bend called the Loop Of Henle. This is located in the medulla of the kidney. As it approaches the top again, hydrogen ions (waste) flow into the tube and down the collecting duct. Essentially, nutrients flow in through the left and exit through the right. Along the way, salts, carbohydrates, and water pass through and are reabsorbed.