What exactly is incontinence and why does it occur? Normally, urine is produced by the kidneys and passes through to the bladder. The tube connected to the bladder that leads the urine to exit the body, is called the urethra. Surrounding the urethra is a ring of muscles called the urinary
sphincter. These muscles contract as the bladder is filling up, and relaxes when it is time for a person to void the contents of the bladder.