What is a nephron, and what does it do?

A nephron is the filtering unit of the human kidneys, and its job is to regulate the concentration of water and soluble substances by filtering the blood. The nephron reabsorbs what the body needs to function and then excretes the rest as urine.

The nephrons work through a two-step process. The glomerulus, or the filter part of the nephron, allows fluids and waste products to flow through it, but it prevents blood cells and large molecules like proteins from passing. The filtered fluid then runs through the tubule where it absorbs the required nutrients from the fluid and removes the waste.