We all tend to take our bladders for granted until they cause problems, but this is actually how its supposed to work. We have enough going on around us, without having to worry constantly about how our bladder is doing.

·Urine is made in the kidney, transported down the ureters, and stored in the bladder until we find a place that is socially acceptable to empty. What is happening most of the time is occurring on a sub-conscious level. Minute by minute, we are not aware that our bladders are slowly filling up. It is not until we reach some amount that we note consciously that our bladder is getting full. Usually, after we reach this amount (which varies widely from person to person), we can continue to "hold" our urine and allow the bladder to continue to fill a little more. Finally we reach a point where no matter how hard we try, we can no longer hold our urine.

Many of us think of the bladder as a balloon that is filling up and if overfull would pop. But, unlike a balloon, as the bladder fills there is no increase in pressure in the bladder. The more air you put into a balloon the harder you have to blow and the greater the pressure. Think of the bladder more as a plastic bag which you can blow into. It fills easily until the bag is full, then suddenly the pressure shoots up and it becomes hard to fill.

It is at capacity when the bladder walls are starting to get stretched, that the bladder starts sending our brain signals that it is getting full. This is mediated through special nerves in the bladder wall called "stretch receptors". When it is appropriate our brains sends a message back to the bladder to empty.