Your urinary tract helps to get rid of your body’s liquid waste. The kidneys constantly filter the blood to collect unneeded chemicals and water, making urine. Urine travels through the ureters to the bladder. The bladder fills with urine, holding it until you’re ready to release it. Signals from the brain tell the sphincter (muscles around the opening of the bladder) when to let urine flow out of the bladder. The urethra is the tube that carries urine from the bladder out of the body. In men, the prostate gland wraps around the urethra near the bladder.