The Physics Factbook™
Edited by Glenn Elert -- Written by his students
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|Bibliographic Entry||Result |
|Curtis, Helena & N. Sue Barnes. Invitation to Biology. 5th Edition. New York: Worth, 1994: 529.||"The human stomach, distended, holds 2 to 4 liters of food."||2–4 L|
|Radcliffe, Donald V. Stomach. Compton's Encyclopeadia Online v3.0. The Learning Company, 1998.||"The stomach of an adult is about 10 inches (25 centimeters) long and can easily expand to hold as much as l quart (0.9 liter) of food."||0.9 L|
|Wenzel, V. et al. Respiratory system compliance decreases after cardiopulmonary resuscitation and stomach inflation: impact of large and small tidal volumes on calculated peak airway pressure. [Medline Abstract] Resuscitation. 38 (August 1998): 113-118.||"Respiratory system compliance was measured at prearrest, after ROSC, and after 2 and 4 l of stomach inflation in the postresuscitation phase; peak airway pressure was subsequently calculated."||2–4 L|
|Bevan, Dr. James. Handbook of Anatomy and Physiology. New York: Simon & Schuster, 1978: 45.||"The stomach is a muscular sac that can contain about 1.5 litres of fluid."||1.5 L|
|Johnson, George B. Holt Biology: Visualizing Life. Orlando: Holt, Rinehart & Winston, 1994: 769.||"The stomach can expand to hold up to 4 L (4.2 qts.) of food, more than 50 times its empty volume."||4 L |
Do you remember the last time you said "Ahhhh, I'm toofull to take another bite." Many of us will probably stopeating, while others may continue stuffing themselves becauseit is a buffet and they want to get their money's worth. The oneswho stop eating might think that the ones who continue are crazy.How can one's stomach fit so much food? The stomach has a lotof functions and one these is to expand and contract.
This J-shaped organ has very active muscles. These musclesexpand and contract depending on how much food is in the stomach.This contraction is a form of mechanical breakdown of the food.The purpose of this breakdown is to increase the available surfacearea for the chemicals to act on it. The gastric glands of thestomach secrete enzymes that perform chemical breakdown, partlydigesting the proteins. Pepsin is the enzyme that breakdown protein.The gastric gland also secretes hydrochloric acid that kills almostall the bacteria in the food. It also secretes mucus that protectsthe stomach wall from the hydrochloric acid. By the time all thefood is mechanically and chemically broken down, the food becomesa semi-fluid substance that leaves the stomach by peristalsisentering the small intestine.
The structure of the stomach is quite unique. It can be dividedinto four subdivisions: the cardia, the fundus, the body, andthe pylorus. The cardia is the region that is closest to the heartand is where the esophagus is connected to the stomach. The fundusis the region that curves above the rest of the stomach (withrespects to a person who is standing upward). The body of thestomach is the largest region located in the center. The pylorusis the region that is connected to the small intestine. The cardiaand the pylorus have sphincter muscles that regulate the movementof food and fluids. You don't want the hydrochloric acid to back up into your esophagus. When you vomit and have a burning sensationin your esophagus, it's the hydrochloric acid from the stomach that causes it.
The volume of the human stomach varies depending on the person.Generally, human stomachs have a volume about one liter, whichis a little more than one quart. Since the stomach has the abilityto expand, it can hold much more food. The human stomach can bedistended up to four liters, which is more than one gallon. Imagineyour stomach to be an empty one-gallon milk carton. There is plentyroom for food! So the next time you go out to an "all youcan eat" restaurant, remember that there is actually moreroom that you think that is available in your stomach. But honestly,stuffing oneself to the limit is not very safe or healthy. Don'tabuse your stomach because you will need it for quite a long time.
Jonathan Cheng -- 2000
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