What sac-like structure temporarily holds urine?

The urinary bladder is a sac-like structure that temporarily holds urine. It is located in the lower abdomen, just above the pelvic floor. The bladder is made up of smooth muscle that can contract and relax to store and release urine. When the bladder is full, it sends signals to the brain that it needs to be emptied. The brain then sends signals to the bladder muscles to contract and the urine is released through the urethra.