The sex organs are also used for urination, which is one of the ways in which the body removes waste products. Both men and women have a bladder, which is an organ that stores urine. In a man, a thin tube called the urethra passes from his bladder right through his penis. In a woman, the urethra opens into the vulva. When a person urinates, urine flows from the bladder through the urethra and out of the body.