Nephron is the basic unit of structure in the kidney. A nephron is used separate to water, ions and small molecules from the blood, filter out wastes and toxins, and return needed molecules to the blood. The nephron functions through ultrafiltration.

A nephron is responsible for removing waste products, stray ions, and excess water from the blood. The blood travels through the glomerulus, which is surrounded by the glomerular capsule. As the heart pumps the blood, the pressure created pushes small molecules through the capillaries and into the glomerular capsule. This is the, more physical function of the nephron. Next, the ultrafiltrate must travel through a winding series of tubules. The cells in each part of the tube have different molecules that they like to absorb. Molecules to be excreted remain in the tubule, while water, glucose and other beneficial molecules work their way back into the bloodstream. As the ultrafiltrate travels down the tubules, the cells become more and more hypertonic compared to the ultrafiltrate. This causes a maximum amount of water to be extracted from the ultrafiltrate before it exits the nephron. The blood surrounding the nephron returns to the body via the interlobular vein, free of toxins and excess substances. The ultrafiltrate is now urine, and moves via the collecting duct to the bladder, where it will be stored.