Comprehensive Guide to Understanding Your Bladder

The bladder is a "storage organ." It is a sac of muscle that sits inside the pelvis. It lies just above and behind the pubic bone. The renal system, including the kidneys and urethra, connect to the bladder; together, these organs facilitate the removal of waste from the body. As one would expect, the bladder is hollow and can expand as more urine accumulates.

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When it is empty of urine, the bladder is roughly the shape and size of a large grapefruit. When it needs to, though, it can expand to a much larger size, only to shrink back once it is empty again. It can hold nearly a half liter of liquid for two to five hours at a time without discomfort. It can hold more if it has to, but this is when we start to feel pressure and the need to urinate.

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When the bladder is full and receives the signal to empty, the muscles in the bladder contract. This causes two valves (sphincters) to open and release a flow of urine. The urine goes into the tube-like urethra, which carries it out of the body. This trip is a bit longer in men than in women: in men, this waste must travel the length of the penis.

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A more complex explanation of how the bladder works involves the other organs of the urinary system, otherwise known as the renal system. The bladder is connected to the kidneys by two long tubes -- the ureters. The kidneys produce urine and send it down along the ureters to the bladder, which holds it until it receives a signal from the brain that it can release it. It then travels down the tubelike urethra and out of the body.

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A healthy bladder empties itself four to eight times per day. This number increases as one ages, as the bladders of older people often begin contracting more often. Urinating every three to four hours is average, although this depends on how many liquids one has taken in on a given day. Most people do not feel the urge to urinate at night even if their bladder is full, as the bladder often "goes to sleep" when they do.

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A healthy bladder can hold up to 600 milliliters of urine. As mentioned previously, it can also expand to many times its original size. This expansion is part of what alerts us to the fact that the bladder needs to empty itself. When our bladders contain 200 to 300 milliliters of urine, we start to feel the need to use the restroom, as the expansion places pressure on surrounding structures. Most people can continue to hold it at this point, but it is better to empty the bladder without putting unnecessary stress on it.

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A healthy bladder needs emptying four to eight times a day on average. It should wake you at night only once at most (two if the person is older), and does not leak any urine. Your bladder should extend the sensation of needing to urinate in time to get to the bathroom without any crises, and it empties completely when you go. It can hold the average amount of urine without any trouble, or any accidents.

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One of the most common bladder conditions is urinary incontinence. Many other medical conditions may cause a bladder to leak or lack the ability to hold in urine. Bed-wetting is a common problem in children. Other conditions and issues that affect the bladder are cystitis (painful inflammation of the bladder), urinary stones, blood in the urine, pain upon urination, and urinary retention. The latter occurs when the bladder is blocked and unable to empty itself properly.

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For decades, people and doctors alike have debated whether or not it is bad to hold urine for extended lengths of time. In the end, holding urine for around an hour is usually okay. However, continuously retaining urine for longer and more intense periods can lead to over-expansion, which can cause problems such as urinary tract infections, deterioration of kidney function, and an inability to completely void the bladder.

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In addition to urinating when you feel the need so as not to overexert the bladder, drinking plenty of water is also helpful in maintaining a healthy bladder. This ensures adequate hydration and the smooth passage of urine through the renal system. It also helps keep all of your other organs healthy and nourished. Regular Kegel exercises may be useful for some, as they exercise the pelvic muscles, helping prevent bladder leakage and urinary incontinence.

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