The kidneys and bladder work together to make urine and remove it from your body. The kidneys filter waste products and water from the blood to form urine. The urine moves from the kidneys through tubes called ureters to the bladder, which stores the urine until it is full. From the bladder, urine leaves the body through another thin tube, the urethra. After the bladder starts to empty, it normally empties all of the urine.