Before we ask ourselves why me? What has caused me to suffer urinary incontinence?
Let’s learn a little about how the urinary system works.

The Kidneys

The kidneys are two bean shaped organs situated at either side of the spine at the lowest level of the rib cage. They are filters, filtering out waste products and water from the bloodstream. The waste and water are filtered into the bladder via the ureters. There is one ureter per kidney, which is the tube that the urine travels from the kidney into the bladder.

The Bladder

The bladder is a balloon like shape that consists of a flexible sac of muscle (the detrusor muscle). The bladder changes shape and expands when it holds urine, and deflates when it is emptied. It lies just under the belly button (navel). In women it lies just in front of the uterus (womb). The bladder of the adult human can hold over a pint (0.6 litres) of urine. When the level of urine reaches about half this amount, pressure of the accumulating fluid stimulates nervous impulses that relax the external sphincter, a muscle that forms a thick band around the urethra at the base of the bladder. Messages are sent from the nerves in the detrusor muscle to the brain via the spinal column telling you that you need to urinate. This can be controlled voluntarily in adults while children learn to control this sphincter. The muscles in the wall of the bladder also contract, forcing urine out through the urethra (the tube that passes the urine from the bladder out of the body.

Sphincters

During storage the urine is retained in the bladder by a ring of two muscles at the bottom of the bladder, called the urethral sphincter, which squeezes shut automatically.

The two mechanisms of the sphincter muscles are:

• The internal sphincter. A ring of muscle that holds the neck of the bladder in place. This opens and closes involuntarily. It is controlled by nerve receptors.
• The external sphincter (distal sphincter) This is opened and shut like a tap, which is controlled by you via the pudendal nerve through the voluntary nervous system.

Bladder function is highly complex. It requires coordination from several parts of the brain and involves both involuntary and voluntary activity. This can be illustrated by looking in more detail at the urethral sphincter. This is made up of two parts each with a different function. The inner sphincter is made up of involuntary muscle; the brain operates this without conscious thought. It maintains a constant steady pressure, squeezing the urethra closed. It is helped by the lining of the urethra which is folded inwards many times so that when compressed it will give a watertight seal. The outer sphincter is made up of muscle, which is under more voluntary control and it is this, along with the pelvic floor that can be consciously squeezed when trying to prevent leakage. Babies do not have this reflex and must learn it. It is capable of very strong contractions but only for a short period of time. The muscle can be fatigued and this is why a sneezing, coughing or any sort of exercise or lifting may cause involuntary leakage.

The Urethra

This is the tube that evacuates urine from the bladder out of the body. It is about 1.5 inches (3.8cm) long in women and about 8 inches (20cm) long in men.