Feces

Feces (fe'sez) are composed of materials that were not digested or absorbed, with water, electrolytes, mucus, and bacteria. Usually the feces are about 75% water, and their color derives from bile pigments altered by bacterial action.

The pungent odor of the feces results from a variety of compounds that bacteria produce. These compounds include phenol, hydrogen sulfide, indole, skatole, and ammonia. Clinical Application 17.5 examines conditions affecting the large intestine.

99 How does peristalsis in the large intestine differ from peristalsis in the small intestine?

Q List the major events that occur during defecation.

H Describe the composition of feces.

The large intestine discomforts as well

Disorders of the Large Intestine

The large intestine discomforts as well

INTESTINAL GAS, Diarrhea, and Constipation

Intestinal gas is 99 percent nitrogen and oxygen taken in while breathing and eating, plus methane (CH4), carbon dioxide (CO2) and hydrogen contributed from the bacterial fermentation of undigested food. The characteristic odor comes from bacterial action on the nitrogen and sulfur in proteins, which yields pungent-smelling ammonia (NH3) and foul hydrogen sulfide (HS). Most people release a half liter of intestinal gas a day, and more if the diet is rich in hard-to-digest foods, such as beans. Foods rich in sulfur-containing amino acids make intestinal gas more foul. These include beans, broccoli, bran, brussels sprouts, cabbage, cauliflower and onions. Eating slowly and avoiding milk if one is lactose intolerant can minimize the production of intestinal gas.

Diarrhea is the frequent and too-rapid passage of loose feces. It results when material moves too quickly through the large intestine, so that too little water is absorbed. Diarrhea is a protective mechanism to flush toxins from the body in case of infection or chemical irritation, but may also occur from nervousness or eating too much fiber.

Constipation is the infrequent passage of hard feces. It results from slowed movement of material through the large intestine, which allows excess water absorption. Constipation can be caused by failure of sensory cells in the rectum to signal the spinal cord, or by conscious sup-

(colon) is the source of familiar digestive as more serious disorders.

pression of the defecation urge, both of which can come from emotional stress. A diet low in fiber can also cause constipation by slowing fecal movement through the large intestine. Eating foods high in fiber, drinking at least eight 8-ounce glasses of water a day, and regular exercise can prevent constipation.

Diverticulosis and Inflammatory Bowel disease

In diverticulosis, parts of the intestinal wall weaken, and the inner mucous membrane protrudes through (fig. 17B). If chyme accumulates in the outpouch-ing and becomes infected (diverticuli-tis), antibiotics or surgical removal of the area may become necessary. Lack of dietary fiber may set the stage for di-

verticulosis. The condition does not occur in populations that eat high fiber diets, and began to appear in the United States only after refined foods were introduced in the middle of the twentieth century.

Inflammatory bowel disease includes ulcerative colitis and Crohn's disease. Ulcerative colitis is an extensive inflammation and ulceration of the large intestine, affecting primarily the mucosa and submucosa. The resulting bouts of bloody diarrhea and cramps may last for days or weeks, and may recur frequently or only very rarely. The severe diarrhea leads to weight loss and electrolyte imbalances, and may develop into colon cancer or affect other organs, including the skin, eyes, or liver. Crohn's disease is similar to ulcera-tive colitis in that it produces diarrhea and abdominal cramps, but the diarrhea may not be bloody, and (continued)

Diverticula
Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

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