Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Ureteral Disorders ?
    ### Response:
    Your kidneys make urine by filtering wastes and extra water from your blood. The urine travels from the kidneys to the bladder in two thin tubes called ureters.    The ureters are about 8 to 10 inches long. Muscles in the ureter walls tighten and relax to force urine down and away from the kidneys.
    