cascade stomach


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stomach

 [stum´ak]
the curved, muscular, saclike structure that is an enlargement of the alimentary canal (see digestive system) and lies between the esophagus and the small intestine; called also gaster. (See also Plates.) adj., adj gas´tric.

The wall of the stomach consists of four coats: an outer serous coat; a muscular coat, made up of longitudinal, circular, and oblique muscle fibers; a submucous coat; and a mucous coat or membrane forming the inner lining. The muscles account for the stomach's ability to expand when food enters it. The muscle fibers slide over one another, reducing the thickness of the wall while increasing its area. When empty, the stomach has practically no cavity at all, since its walls are pressed tightly together; when full it holds about 1.4 liters.

The stomach muscles perform another function. When food enters the stomach, they contract in rhythm and their combined action sends a series of wavelike contractions from the upper end of the stomach to the lower end. These contractions, known as peristalsis, mix the partially digested food with the stomach secretions and ingested liquid until it has the consistency of a thick soup; the contractions then push it gradually by small aliquots into the small intestine.

The stomach is usually emptied of its digested contents in 1 to 4 hours; the time may be longer, however, depending on the amount and type of food eaten. Foods rich in carbohydrates leave it more rapidly than proteins, and proteins more rapidly than fats. The stomach may continue to contract after it is empty; such contractions stimulate nerves in its wall and may cause hunger pangs.

The mucous membrane lining the stomach contains innumerable gastric glands; their secretion, gastric juice, contains enzymes, mucin, and hydrochloric acid. Enzymes help to split the food molecules into smaller parts during digestion. The physiologic action of mucin is not fully understood. Hydrochloric acid aids in dissolving the food before the enzymes begin working on it.

The diagnosis and treatment of stomach disorders has changed markedly with the development of endoscopy. This benign procedure permits direct examination and biopsy of the stomach and has sharply increased the accuracy of diagnosis and, as a result, the effectiveness of medical therapy. In addition, the development of whole new families of medications that reduce gastric acid secretion (such as cimetidine) and increase gastric motility (such as metoclopramide) have decreased the need for surgery for peptic ulcer disease.

Surgery of the stomach has become increasingly conservative with a better understanding of that organ's physiology. Instead of the resections that were once done routinely for peptic ulcer disease, sophisticated procedures, such as the supraselective vagotomy, that can decrease acid secretion without resection of the stomach are available. Even so, resection may still be needed for more severe cases of ulcer disease, for such complex entities as Zollinger-Ellison syndrome, and for malignancies.
Anatomy of the stomach. From Ignatavicius and Workman, 2002.
cascade stomach an atypical form of hourglass stomach, characterized radiologically by a drawing up of the posterior wall; an opaque medium first fills the upper sac and then cascades into the lower sac.
hourglass stomach one shaped somewhat like an hourglass.
leather bottle stomach linitis plastica.
stomach pump an apparatus used to remove material from the stomach, consisting of a stomach tube to which a bulb syringe is attached. The tube is inserted into the mouth or nose and passed down the esophagus into the stomach. Suction from the syringe brings the contents of the stomach up through the tube. This can be used either to remove material from the stomach in an emergency (such as when a person has swallowed poison) or to obtain a specimen for chemical analysis (such as in diagnosis of peptic ulcer or other stomach disorders).
stomach tube a flexible tube used for introducing food, medication, or other material directly into the stomach. It can be passed into the stomach by way of either the nose or the mouth. See also tube feeding. Called also esophageal tube.

cas·cade stom·ach

a radiographic description: when contrast material is swallowed while the patient is in the upright position, the gastric fundus acts as a reservoir until contrast overflows (cascades) into the antrum; a normal variant in a horizontal stomach.

cas·cade stom·ach

(kas-kād' stŏm'ăk)
A radiographic description: when contrast material is swallowed while the patient is in the upright position, the gastric fundus acts as a reservoir until contrast overflows (cascades) into the antrum; a normal variant in a horizontal stomach.

cascade stomach

A form of hourglass stomach in which there is a constriction between the cardiac and pyloric portions. The cardiac portion fills first, and then the contents cascade into the pyloric portion.
See also: stomach