Because the Kidneys are one of the most vital organs in the human body after the heart, their absence or malfunction can lead to extreme illness and even death. The Kidney has a very complicated structure and complex functions for this reason. The Kidneys purify waste materials and toxic substances from the blood, thereby keeping the body clean and healthy. The Kidneys create urine by this process, and sends it to the ureter, where it passes through the urethra, and out of the body.
People generally have two Kidneys. The Kidneys are located deep in the upper abdomen on either side of the spine, and are protected by the rib cage. They are bean shaped, and are about 10 cm long, 6 cm high, and 4 cm wide in normal adults. The Kidneys create urine from filtered blood, and they send the urine to the bladder through the ureter. The ureter is a hollow muscular tube that is about 25 cm long. The bladder is a hollow, muscular organ which lies in the lower back part of the abdomen. It temporarily stores urine.