The Physics Factbook™
Edited by Glenn Elert -- Written by his students
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|Bibliographic Entry||Result |
|Hole, John W. Human Anatomy and Physiology. 2nd ed. Dubuque, IA: WCB, 1981.||"Although the urinary bladder may hold as much as 600 ml of urine, the desire to urinate is usually experienced when it contains about 150 ml."||600 cm3 |
|Encyclopedia Americana - International Edition. Danbury, CT: Grolier, 2001.||"When it is completely filled, the bladder can hold approximately 17 to 18 ounces (500 to 530 ml) of urine."||500–530 cm3 |
|Magill's Medical Guide Volume III. Englewood Cliffs, NJ: Salem, 1998.||"A completely full bladder is capable of holding approximately 1 liter of fluid … Ordinarily the urge to urinate occurs when the bladder contains about 200 ml of urine."||1000 cm3 |
|Gray, Henry F.R.S. Gray's Anatomy - 1901 Edition. Philadelphia: Carriage, 1974.||When moderately distended, it measures about five inches in length and three inches across, and the ordinary amount which it contains is about a pint."||470 cm3|
|Urinary Bladder. Britannica.com.||"The desire to micturate begins at around a content of 400 ml but it can be voluntarily overridden until the content reaches 600–800 ml, equivalent to a pressure of 100 ml of water.||600-800 cm3 |
There's a great scene in an episode of The Cosby Showwhere Mr. Huxtable is dressing his daughter to go play out inthe snow. Like a good father, he dresses her appropriately forthe cold weather. With every layer he puts on her he asks "Doyou have to go to the bathroom?"Seven layers and seven questionslater, the daughter innocently says "Dad, I have to pee!"and begins to undress.
It's almost impossible to give an exact measurement for thevolume of the human bladder. That is, everyone's ability to holda certain amount of urine differs. The point at which a personcan't "hold it in"anymore and urine is expelled fromthe urinary bladder is known as Micturition. The urge to urinateis stimulated by expansion of of the bladder. As the bladder wallsfill with urine and expand, stretch receptors are stimulated andthe Micturition reflex is triggered. The Micturition reflex centeris located in the spinal cord. When it is signaled by impulsesfrom the stretch receptors, motor impulses travel to a musclein the urinary bladder which undergoes rhythmic contractions.It is interesting to note that the reason infants are unable tocontrol the voluntary muscles associated with Micturition is becausevoluntary control of Micturition becomes possible as the brainand spinal cord mature.
The majority of sources that I found reported that the adultbladder could contain about 600 to 800 cm3 (ml).However, they also noted that the Micturition point is between150 and 300 cm3 (ml).
Daniel Shaw -- 2001
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