Adult continence, or the process of maintaining  control over urination, is an acquired complex process. Nature’s design is for the urination process to occur automatically. This is how infants, children, and even animals empty their urinary bladders.

The urinary bladder wall is mainly made up of muscles which are sensitive to stretch. As urine trickles down from the ureters, the tubes that carry it from the kidneys, it slowly fills the bladder. When the bladder is sufficiently filled with urine, the receptors in its muscle wall are stimulated and fire a signal which reaches the spinal cord.  This signal initiates the urination reflex which results in the contraction of the bladder muscle leading to the automatic emptying of the bladder.  The Adult continence develops only when the person is able to inhibit this contraction process. The brain signals from above instruct the bladder wall to relax again until the time is right.