How Your Body Makes, Stores, and Releases Urine
When you eat and drink, your body absorbs the liquid. The kidneys filter out waste products from the body fluids and make urine.
Urine travels down tubes called ureters into a muscular sac called the urinary bladder, which stores the urine.
When you are ready to go to the bathroom, your brain tells your system to relax.
Urine travels out of your bladder through a tube called the urethra. You release urine by relaxing the urethral sphincter and contracting the bladder muscles. The urethral sphincter is a group of muscles that tightens to hold urine in and loosens to let it out.