The Urinary Tract
The kidneys are bean-shaped organs, each about four to five inches (12 centimeters) long. They are located on each side of the spinal column, behind the digestive organs. Each kidney receives blood through a branch of the aorta, called the renal artery. Blood flows from the renal artery into smaller arteries and then into microscopic blood vessels called capillaries. Blood exits through small veins that join to form a single, large renal vein. The renal veins carry blood away from the kidneys.