We have two kidneys, each about a size of a fist, located on either side of the spine at the bottom of the rib cage. Urine is produced by the kidneys and it passes from the kidneys into the bladder through two tubes called the ureters. It then leaves the bladder through another tube called the urethra. Each kidney contains about one million functioning units called nephrons. A nephron contains a filtering complex of tiny blood vessels called glomerulus. Blood is filtered in the glomerulus where waste products pass through the tubule to eventually form urine. The outer portion of the kidney called cortex contains the glomeruli. The tubules are located in the cortex and medulla. Urine travels from the collecting tubules into the renal pelvis, ureter, and bladder.
Filtered and cleaned blood returns back to the circulation via renal vein.
