The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible (or elastic) organ, the bladder sits on the pelvic floor. Urine enters the bladder via the ureters and exits via the urethra. There is no exact measurement for the volume of the human bladder, but different sources mention 500 mL (~17 oz) to 1000 mL (~34 oz).