Understanding the Bladder
What is going on down there?
It all starts in the lower urinary tract, which is responsible for storing urine and then expelling urine to the outside of the body. It is composed of the bladder which actually holds the urine (like a reservoir) and the urethra and pelvic floor muscles which help keep urine in the bladder until it is time to empty it (together they act as the dam for the reservoir).
The bladder has 2 functions: it stores urine and it empties urine to the outside of the body.
How big is the bladder?
An adult bladder, when full, would be the size of a large grapefruit or small melon. The bladder is a hollow sphere-like organ composed of muscle fibers that relax to allow you to “hold it” and then contract to let you go to the bathroom.
How often does a “normal” person go to the bathroom?
Going to the bathroom frequently does not mean you have a small bladder. The amount of urine produced by the kidneys dependent on how much fluid you are drinking and vice versa. When someone is adequately hydrated to maintain normal bodily functions, the amount of urine produced should trigger the need to go every 3 to 4 hours during the day.
Your bladder can be irritable.
The bladder is a balloon like structure composed of muscles on the outside and a lining on the inside that has nerve ending right underneath. The bladder lining is not impermeable like plastic…it is more like the lining of your mouth. Imagine drinking lemon juice and you’ll instantly feel the need to pucker. However, drinking a glass of water with a lemon slice should leave you with no reaction. Your bladder reacts the same way: when the urine is very dilute, the bladder does not react to it – and it will gladly keep holding more until it reaches its capacity. When the urine is concentrated (like after drinking a BIG cup of morning coffee), the reaction may be to send a message to the brain saying “let’s get rid of this!” If the bladder is very irritated, the bladder may go straight to a pucker and try to expel the contents it does not like.
Be kind to your bladder
People commonly develop the habit of making their bladder adapt to their needs and schedules without realizing there may be long term consequences. These consequences may not be apparent until later in life when there is gradual deterioration in nerve and muscle function throughout the body.
Ignoring signals from your bladder will gradually increase the bladder capacity overtime. However, the bladder muscle can stretch and may not be able to squeeze well enough to empty completely.
On the other hand, using the restroom every time you feel the desire to urinate can train your bladder to feel full at small volumes and result in frequent urination.
An adult bladder has about a 1.5 to 2 cup capacity. The feeling that you will have to go soon occurs at ¾ of a cup, greater urge starting at about 1.25 cups and a strong desire at 1.5-2 cups. The bladder can hold much larger amounts and the sense of urge will build and at times can become quite uncomfortable. But the bladder should not empty until given permission to do so.
Special thanks to Dr. Tamara Bavendam, Medical Director, Pfizer, for her contributions.
This information is not intended to substitute the recommendations of
your healthcare providers. Women’s Health Foundation disclaims any
liability for the decisions you make based on this information.
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