The system that collects the liquid wastes and helps the body to get rid of them is called the urinary or excretory system. The main organs of this system are the two kidneys which are located one on each side of the waist or lower abdomen. The kidneys filter out the wastes from the blood. Tubes called the ureter bring the wastes from the kidneys to the urinary bladder. The wastes gare passed out from the bladder in the form of urine.