Bladder Anatomy
Urine flows from the kidneys, through the ureters, and into the bladder. As the bladder fills, the bladder wall stretches. This sensation results in the urge to urinate. The act of urination causes the bladder to empty into the urethra. Urine flows through the urethra and exits the body.

Anatomy of the bladder:

• Female bladder
• Male bladder and prostate

The bladder holds 10 to 20 ounces (300 to 600 ml) of urine.