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Positive Options FOR CROHN'S DISEASESelf-Help and Treatment
By Joan Gomez
Hunter House Inc., PublishersCopyright © 2000 Joan Gomez
All right reserved.
Chapter OneThe Digestive System: How It Works
Imagine a life without eating and drinking-it wouldn't be much fun at all. You would miss out on a recurrent pleasure, a comfort in distress, and the focus of much of our social life, from a formal banquet or a candlelit supper for two to pizza with the family. Yet, for happy eating, you need a digestive system in good working order. It has to perform the everyday chemical magic of turning pizza and apple pie, or whatever you choose, into blood, brain, and bone-all manufactured to your own individual specifications.
To accomplish this miracle, the different parts of the digestive system must coordinate their separate tasks. The timing is crucial: the food must pass down the alimentary tract (the pathway through the digestive system) at exactly the right rate for the processing of each of the varied ingredients of your meal-proteins, carbohydrates, and fats-to be completed. All of this would be pointless without the next stage, the absorption of the processed nutrients into the bloodstream, so that your body can use them. The main area for absorption is the small intestine, the part most seriously affected by Crohn's. The final task of the digestive system is the disposal of the waste matter-down the toilet.
Crohn's disease upsets all of this-absorption in particular, but also the basic work of digestion and elimination-including the time frame. To understand Crohn's it helps to know the main parts of the digestive system and what they do. Besides, it is a fascinating story.
THE ALIMENTARY TRACT
The system operates under computer control. The computer is your brain, and it keeps in touch with every part through the nervous system. The two ends of the alimentary tract, the mouth and the anus, work in response to your conscious decisions-to eat and to go to the toilet. All the rest comes under the influence of the autonomic (automatic) nervous system, and most of the activity is reflex, like a knee jerk. That is, given a particular stimulus, in this case tapping the front of your knee, your knee jerks automatically. You don't have to give it a thought.
Similarly, but in a much more complex way, the arrival of a steak or a piece of chicken in your stomach stimulates a reflex reaction in the stomach glands. They produce just the right amount of the digestive enzyme pepsin to digest the type and amount of protein. Imagine how tiresome it would be if you had to weigh and analyze what you ate, and then had to sit down with pencil and paper to work out which digestive enzymes you would need and the quantities. Instead, the whole system runs on a series of reflexes.
Although Burrill Crohn in the 1930s believed Crohn's could affect only the last few inches of the ileum, the terminal part, by the 1960s other doctors had found that the telltale patches of inflammation could show up anywhere in the alimentary tract. The effects-including your symptoms-differ according to the site of the trouble.
This is the entry point for food, where tasting and savoring help you to decide whether to go ahead and enjoy or spit it out. One job of the mouth is to smash and crunch up the food: this allows the digestive juices to reach all parts of it and also makes it easier to swallow. The other important task depends on the salivary glands, the saliva factories, which output about a quart per day. This slippery fluid lubricates each mouthful, making for easy transit down the esophagus (gullet) to the stomach. Saliva also contributes to oral hygiene by preventing crumbs of food sticking to the lining of the mouth and by washing away the germs that abound in the mouth.
Saliva has another useful role. It contains ptyalin, an enzyme that digests starch. You can test this out for yourself by chewing a piece of bread extra thoroughly. You will find it begins to taste sweet as the starch is digested into sugar. Our grandparents had a point when they advised us to chew every mouthful 32 times, making a mush with the saliva well mixed in and giving it time to work on the starch. An excellent start to digestion.
The salivary glands go into production when they receive information from the brain about the imminent arrival of food. My cat Emma dribbles in anticipation when she sees me open a can of cat food. Our human reflexes are similar, and we speak of something delicious as "mouth-watering." The actual presence of food in the mouth also promotes the flow of saliva. Another stimulus to the flow of saliva is when the stomach has been irritated and you feel nauseous. The extra saliva helps to flush out the harmful material, or at least dilutes it.
This flexible, collapsible tube connects the mouth with the stomach. It is lined, like the whole of the alimentary tract, by moist, delicate mucous membrane. Mucous glands down its length provide it with a protective covering. Food does not just fall down from the mouth to the stomach, but is massaged along by the muscles in the wall of the esophagus. This is called peristalsis and is a feature of the whole alimentary tract. It makes it possible for circus performers to drink a glass of water while standing on their heads. You can feel the peristalsis working if you accidentally swallow a cherry pit or swallow a mouthful of food without chewing it.
The "law of the gut" is that throughout the alimentary tract, and most obviously in the esophagus and the intestines, peristalsis moves the contents continuously onward in the direction of the anus.
Lorna Lorna had coped with her typical Crohn's quite effectively with the help of the standard drugs since age 22. It was when she was 28 that some new symptoms appeared. Swallowing became uncomfortable, then increasingly difficult, and she had an irritating cough. She lost about ten pounds and looked ill. X-rays and passing an endoscope into her esophagus showed Crohn's disease esophagitis, with numerous small ulcers and a narrowing caused by a ring of swollen, inflamed tissue mixed with scarring. The treatment consisted of gently stretching this area by passing bougies (pencil-shaped instruments for pushing into narrow or blocked tubes) of increasing size through it. After five sessions Lorna was able to swallow normally again. Her medication was also adjusted, and she soon entered a long period of remission.
As food travels down the esophagus a message flashes forward to the stomach: "Food on the way." The stomach muscles relax, especially at the entrance, and stomach glands begin to produce the appropriate digestive juices to deal with the type of food that is arriving.
The stomach serves several important functions:
1. As a storage chamber for large quantities of food, so that you do not have to chomp all the time like a cow, but can take in all you need for 24 hours at three or four meals. 2. Production of digestive juices, including hydrochloric acid to soften tough material, and pepsin to digest protein. This combination could be damaging to the body's own tissues, which is why there is a ring of muscle, the pylorus, that prevents the stomach contents from running back into the esophagus. The stomach lining is especially well coated with extrastrength mucous to protect it against the acid and pepsin. In the duodenum, just past the exit from the stomach, the bile duct pours out its secretions. Bile is strongly alkaline and neutralizes stomach acid. The stomach enzymes can digest carbohydrates as well as proteins. 3. Production of intrinsic factor, another constituent of the stomach juices. This is necessary for the absorption of vitamin B12, without which a serious form of anemia develops called pernicious anemia. 4. Kneading and thoroughly mixing the food and the stomach juices, for as long as necessary, to produce a milky-looking semifluid called chyme. 5. Slow, controlled emptying of the chyme into the small intestine, as and when facilities for the next stage become available. There must obviously be room, and the rate of emptying is geared to allow for the digestive process to continue until the chyme is ready for absorption. 6. The correct rate of transit is of key importance to the digestive process, and nervous messages are sent both ways between the stomach and the small intestine to communicate, for instance, information that the chyme is still too acidic or contains too much undigested fat or protein-or is irritating for some other reason. 7. Stomach reflexes: the automatic message from the stomach to the small intestine is called the gastroenteric reflex, while the reverse, the enterogastric reflex, tells the stomach to turn off the production of acid and pepsin, because the chyme has moved into the intestine. (Any strong emotion has an equally powerful switch-off effect on the stomach.) Messages from the stomach to the colon set off the gastrocolic reflex. This alerts the colon to the arrival into the system of another meal, and this is often a good time to get rid of accumulated waste matter as, for instance, the after-breakfast bowel movement.
The Small Intestine
The small intestine comprises, in order, the duodenum, the jejunum, and the ileum. Its smallness refers to the relative narrowness of the tube compared with the much wider colon or large intestine, but it is many times longer. The gastroenteric reflex stimulates increased peristalsis in the small intestine, especially the jejunum. The normal travel time from the stomach through the small intestine to the caecum, where the large intestine begins, is between three and five hours, depending on the type and quantity of food in the system.
The duodenum is only a few inches long, little more than a lobby to the stomach. Partly because it is more exposed to the stomach juices than the lower parts of the intestine, ulcers often develop here. The most important role of the duodenum is the reception, through the bile duct, of digestive juices from the pancreas, and of bile made by the liver and stored in the gall bladder. The pancreatic enzymes aid in the digestion of all three kinds of foodstuff-proteins, fats, and carbohydrates. Bile is essential for the digestion and preparation for absorption of fats, a necessary requirement for the body to obtain its supplies of the fat-soluble vitamins: A, D, E, and K. The gall bladder automatically pours out all the bile it is storing when a fatty meal arrives in the duodenum.
The jejunum and ileum comprise the rest of the small intestine, coils many feet long. In the jejunum, located just after the duodenum, peristalsis is vigorous, and so are other muscular movements, ensuring that the chyme is thoroughly mixed with the digestive juices to make a runny mishmash. The digestive process continues as the chyme travels through the jejunum and is virtually complete when it reaches the ileum, the organ most affected by Crohn's. The ileum has the important task of absorbing almost all the nutrients from the chyme into the bloodstream, a role for which it is specifically adapted.
Its lining is covered with tiny, delicate fingers of tissue that both release liquid and reabsorb it when it is loaded with nourishment from the chyme. Another special feature of the cells lining the small intestine is their short life-five to seven days. The advantage of this is that any damage is quickly repaired with brand new cells, indicating how indispensable the ileum is to life. If there is some irritation in the small intestine, such as inflammation or the presence of bacteria, the movement of the chyme is speeded up, resulting in copious, watery diarrhea. This washes out germs or other irritants, but also causes the loss of essential nourishment.
Every day, when you are in normal health, your ileum absorbs into the bloodstream:
several hundred grams of carbohydrate (100 g is equivalent to 3.5 ounces, or nearly a quarter pound) 100 g of fat 50-100 g of protein constituents (amino acids) 50-100 g of chemical ions, such as iron, calcium, and magnesium all the vitamins (naturally occurring compounds needed in small quantities for normal metabolism and bodily function, but which the human body cannot make for itself) 7-8 liters of fluid (a liter is the equivalent of about a quart)
The ileum is capable of absorbing much larger quantities if necessary: up to 20 liters of water in a day, for instance. Although the ileum is the main area for absorption, other parts of the digestive system can take in some substances. The stomach, for example, can absorb alcohol-the reason for its rapid effect-and several drugs, such as aspirin, and the duodenum absorbs calcium, so long as there is also some vitamin D available. The colon can only absorb water and a few simple chemicals dissolved in it.
The Large Intestine
The ileum ends in the ileocaecal junction, where there is a double ring of muscles to regulate when and at what rate the now depleted chyme is allowed through. It is reduced to about 1 1/2 liters (1,500 ml) daily. The caecum is a bulge that marks the beginning of the large intestine. It is in the lower right-hand corner of the abdomen, and the appendix is a short dead-end alley that comes off it. The caecum continues as the colon until it becomes the specialized end section, the rectum, and the final exit, the anus.
The first half of the colon is called the "absorbing colon" since it absorbs most of the water and chemicals entering it, leaving about 100 ml for the waste mixture, the stool or feces. The second part is the "storage colon" where the waste is kept until there is a signal that it is time to empty it. There are normally many bacteria in the colon, especially "colon bacilli," and they are responsible for the gas or flatus that can be so embarrassing, produced from various foods such as beans, cabbage, and unabsorbable roughage.
The only material produced in the colon is mucous, and its lining is massed with mucous cells. These are stimulated by the presence of waste matter, and the mucous protects and lubricates the lining. It also helps to bind the waste-or fecal-matter together, for convenience in storage and disposal. The contents of the colon are semiliquid at the caecal end, mushy in the middle, and semisolid when they reach the rectum.
When the colon is irritated by inflammation, enteritis (inflammation of the ileum), or inadequately digested material, it reacts by pouring out more mucous and speeding up the passage of its contents by mass movements involving its whole length. Emotional disturbances stimulate the colon to produce a large amount of stringy mucous, which produces the urge to pass stool as often as every half hour-even if there is nothing to pass.
Andrew Andrew was a conscientious 18-year-old, predictably nervous about final exams. He had always had a tendency to suffer from diarrhea when he was upset as a child, so no one took much notice when it happened this time. However, after one sharp attack the symptoms kept recurring, and he noticed that his stool contained bloodstained mucous and pus. Andrew had Crohn's disease affecting his colon, or Crohn's colitis. It responded well to a drug called sulfasalazine, an old favorite in the treatment of Crohn's.
The rectum and anus comprise the final parts of the alimentary tract and differ from the previous sections in that you have some conscious control over them. The sensitive rectum informs you when it is full and reminds you to go to the toilet. The muscle of the anus has to relax to allow the bowel movement to pass, and this is under your control so that you can wait for a convenient time and place. The anal region is especially sensitive, and inflammation here, proctitis, can be so painful that the sufferer may be afraid to let the stool pass.
Excerpted from Positive Options FOR CROHN'S DISEASE by Joan Gomez Copyright © 2000 by Joan Gomez. Excerpted by permission.
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