The urinary system is built up of many organs, one the first one is the Kidney, then comes the Ureter, which is followed bu the Bladder and at last comes the Urethra. The urine flows through the Kidney which filters waste wastes from the Blood flow in the body, then it makes its way down the Ureter which are tubes that help the urine flow through the system till it makes its way into the bladder which holds the urine until it can be released, after that is heads down to the Urethra which then disposes of the urine, with males it also disposes of semen.
