HANDS DOWN, I would win any contest for the least glamorous organ in the human body. I am a constant source of annoyance and embarrassment to you. I am a sleep spoiler - getting you out of bed on cold nights. At important business conferences I speak with greater authority than your boss or clients. They may have important messages, but mine take precedence. I don't ask for attention. I demand it. I am your bladder.
You think of your intestine as your main waste-disposal system, but your wrong. That tract might go on strike for a week - or in extreme cases for several weeks - and you wouldn't necessarily face any grave danger. But let your urinary system close shop for more than a few days and you would be in real trouble.
When full I am roughly the shape of a punching bag. Bladder capacity varies with individuals - from 6 to 24 ounces. If you are in the normal range - about a pint. Day and night, kidneys dribble urine into me as they filter wastes from blood. It comes via two tiny ureters - tubes about the size of pencil leads and 12 inches long. My exit to the outside is the pencil-size urethra. The amount of fluid I empty through it each day varies tremendously - from one pint to two gallons.
If you're about average - three pints. But this can vary. The volume is largely determined by fluid losses from sweat glands and lungs. When you perspire my production falls. Fortunately for you, urine production also drops during sleep to about a quarter of daytime levels. Otherwise you wouldn't get much rest. When I empty, muscles at the top contract first, then those below add their squeeze. In effect, I wring myself out. How often I do so is determined by many things. Worry, anxiety and fear hoist blood pressure and thereby step up kidney activity and production of urine. Mental stresses, the excitement of a ball game or anger tend to tighten my muscular walls. I may not be full but wish to be relieved just the same.
When your mother was pregnant, you in effect sat on her bladder, and under this constant pressure her calls were many. You may recall that on cold days I give frequent distress signals. What happens is this: to conserve heat, your bloodstream detours skin blood vessels. More goes to internal organs. As kidneys filter more blood they produce more urine. Certain condiments also irritate me - mustard, pepper and ginger particularly, and even tea and coffee. Alcohol is similarly irritating, particularly the flavorings in gin. An examination of my urine can reveal an enormous amount about what is happening elsewhere in your body.
Everything considered, it is probably the most valuable of all medical tests. If you notice that your urine is persistently cloudy, malodorous or discolored, you would be well advised to consult a physician. Is urine water deep amber? This may mean that the kidneys are doing too good a job of concentration, or only that you have been playing tennis and sweating so heavily that you haven't a lot of fluid left for the kidneys to dispose of. Is it cloudy? This may indicate kidney sickness or can be meaningless. Urine tends to cloud after heavy exercise. Is there blood in urine? This can be deadly serious. If you ever find this, you should get to a doctor and fast.