Kidneys

The kidneys are a filter for the blood. The body has two kidneys located in the middle of the back at about the location of your elbows. Blood is pumped from the heart to the kidneys to be cleaned. Each kidney has about 1000 nephrons that act as filters. As the blood goes into a nephron, everything that is dissolved in the blood (waste products, food) is pushed out of the blood into small tubules. As these things travel through the tubule, the water and anything else the body needs goes back into the blood. The rest of the waste products keep moving through the tubule into the urethra. The urethra is the tube that leads to the bladder. The cleaned blood leaves the kidney and travels throughout the body.