A nephron is a tiny unit inside the kidney that filters the blood and regulates how much water, sugars, and salts flow through the body. It helps absorb what the body needs and excretes the rest through urine.
Within each kidney there are about one million nephrons. Each one of them is made up of a glomerulus. This is a filtering funnel that's made up of a group of small blood capillaries. The glomerulus is held in a Bowman's capsule that has a long, narrow tubule. This is the renal tubule. An ultrafiltration process pushes water and wastes through this tubule, while pressure forces blood into the kidney. From here the important molecules the body needs are absorbed back into the bloodstream and what is left enters the bladder to exit the body.