removal of too much water from them. Diarrhea results when movement of the
intestinal contents is so rapid that not enough water is removed.
1-10. THE RECTUM AND ANUS
The rectum is about 5 inches long and follows the curve of the sacrum and
coccyx until it bends back into the short anal canal. The anus is the external opening at
the lower end of the digestive system. It is kept closed by a strong sphincter muscle.
The rectum receives feces and periodically expels this material through the anus. This
elimination of refuse is called defecation.
1-11. DEFECATION
The passage of feces is called defecation. It is begun voluntarily by contraction
of the abdominal muscles. At the same time, the sphincter muscles of the anus relax,
and there is a peristaltic contraction wave of the colon and rectum. Feces are expelled
as a result of all these actions. Feces consist of undigested food residue, secretions
from the digestive glands, bile, mucus, and millions of bacteria. Mucus is derived from
the many mucous glands that pour secretions into the intestine. Bacteria are especially
numerous in the large intestine. They act upon food material, causing putrefaction of
proteins and fermentation of carbohydrates. Although the bacteria normally in the large
intestine serve a useful purpose internally, they are contaminants outside the intestine.
1-12. TIME REQUIRED FOR DIGESTION
Within a few minutes after a meal reaches the stomach, it begins to pass through
the lower valve of the stomach. After the first hour the stomach is half-empty, and at the
end of the sixth hour none of the meal is present in the stomach. The meal goes
through the small intestine, and the first part of it reaches the cecum in 20 minutes to 2
hours. At the end of the sixth hour, most of it should have passed into the colon; in 12
hours, all should be in the colon. Twenty-four hours from the time when food is eaten,
the meal should reach the rectum. However, part of a meal may be defecated at one
time and the rest at another.
Section II.
NURSING ASSESSMENT
1-13. GENERAL
The vague nature of many gastrointestinal symptoms makes diagnosis of GI
problems quite difficult. A complete patient history and an adequate physical
examination are necessary in order to gather as much information as possible.
Although this is routinely done by the admitting physician, a nursing assessment must
be completed as well. Patients will quite often neglect to mention facts, which they
consider insignificant, unimportant, or irrelevant. A detailed nursing interview may elicit
previously unmentioned, valuable information.
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