”I am Your Body”

STOMACH

    
YOU FRET about me more than any other organ in your body. You think I am terribly important. Actually, I am mostly just a convenience- a food reservoir that permits you to get by on three meals a day, instead of the half dozen or more you would need without me. So far as digestion is concerned, the small intestine is the real champ.
I am your stomach. I work on protein, breaking it down into polypeptides, but even here the final job is done by the intestine, which also takes care of carbohydrates, fats and other foods.
I'm afraid I'm not a very inspiring sight. I'm glossy pink outside. Inside, I look like folds of glistening velvet. Tucked up the abdomen at the lower rib line, I resemble a deflated balloon when I'm empty. When I'm full, I slant across the body, big at top, small at bottom, shaped roughly like a bulbous letter J. My capacity is a little less than two quarts. a Newfoundland dog can hold three times as much.

Although I am not as important as you think, I do perform a number of jobs that make life pleasant. My lining contains some 35 million glands that may secrete about three quarts of gastric juice per day - mainly hydrochloric acid. The acid serves to activate another of my secretions - the enzyme pepsin, which starts protein digestion. Without pepsin, you would have a hard time with that steak you love so much. My glands secrete other enzymes as well. One, for example, clots milk, converting it into easily digestible curds and whey.

Everyone thinks of me as a violent churn, which manhandles everything that you swallow. Not so. As you eat dinner, the food is deposited one layer at a time: the shrimp cocktail first; then the meat, potatoes and vegetables; then the apple pie. I start work on the shrimps that lie against my wall. My muscular contractions, sweeping wavelike from top to bottom, mix them thoroughly with digestive juices. Pretty soon they are a thick gruel. Gradually, I work this gruel down toward the pyloric valve, which opens into the duodenum, the foot-long first part of the small intestine.

This is a dangerous spot. If any large amount of gastric juice is dumped into the duodenum, it eats its way into the wall. That's why this is the commonest site of ulcers. Fortunately for you, my pyloric valve lets food through in little squirts - no more than can be instantly neutralized by the normally alkaline duodenum.

The mashed potatoes take me only a few minutes to handle. Meat takes longer, and leafy vegetables still longer. How long? There is enormous variation, and much depends on your mood. But four hours will probably be average for the meal described. If spinach, however, is included, it may stay around as long as 24 hours.

Fatty meals pose special problems. Suppose, that at 7 A.M. you eat a breakfast of eggs scrambled in butter and cream, bacon and well-buttered toast. This excess of fat triggers the duodenum to produce a hormone that slows my muscular contraction, probably in self-protection. It can't handle such a big load of fat all at once. As a result, when you sit down for lunch, I may still be working on as much as a fourth of you]re breakfast.

Another thing that slows me is cold. If you eat a big dish of ice cream, I can cool down as much as 20 degrees from a normal 99 degrees F, and everything comes to a halt for the half hour it takes me to warm up again. But no harm is done. After all, I am in no particular hurry.

In fact, I lead a pretty relaxed life. While liver, heart, lungs and kidneys keep at it 24 hours a day, I can finish my work on a normal dinner by the time you go to bed. So I go to sleep when you do.

A question arises: Since I digest other proteins, why don't I digest myself (After all, I handle tripe quite nicely, and that is cow's stomach.) The reason is that my delicate lining is coated with a protective mucus. Scrape it away, and I turn cannibal.

I have another remarkable attribute: the way I reflect your moods. When your face turns red with anger, I turn red. When you get pale with fright, I get pale, too. When you get excited at a football game, I react with vigorous contractions - my secretions may triple in volume. When, you smell a chop broiling or see delicious-looking pastries in a bakery shop, I go into action. You call these hunger pains, and you may just be right.

I share your depressions, too - my muscular waves all but stop, and so does secretion of gastric juice. Out of habit, however, you continue to eat. And what you swallow just sits there, causing distention and discomfort. In times like these, you would do better off not to eat at all.

Stressful situations produce a different problem: They hoist acid production, sometimes to the point of causing an ulcer. Whenever you're under stress, you would be wise to shift eating habits. Eating a number of small, light meals is the best way to control excess acid. Actually, you had a minor ulcer once, and didn't t even know it. This happens to many people. Most likely when you where in college and worried about exams, this shot my acid production up, and the acid finally found a tiny weak spot in the mucus. You had a few twinges of pain and attributed them to sketchy eating. But once exams were over and you calmed down, acid secretion dropped, and I got a chance to pour out mucus and heal my wound.

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