gastric juice


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gastric juice,

thin, strongly acidic (pH varying from 1 to 3), almost colorless liquid secreted by the glands in the lining of the stomach. Its essential constituents are the digestive enzymes pepsinpepsin,
enzyme produced in the mucosal lining of the stomach that acts to degrade protein. Pepsin is one of three principal protein-degrading, or proteolytic, enzymes in the digestive system, the other two being chymotrypsin and trypsin.
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 and rennin (see rennetrennet,
substance containing rennin, an enzyme having the property of clotting, or curdling, milk. It is used in the making of cheese and junket. Rennet is obtained from the stomachs of young mammals living on milk, especially from the inner lining of the fourth, or true,
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), hydrochloric acid, and mucus. Pepsin converts proteins into simpler, more easily absorbed substances; it is aided in this by hydrochloric acid, which provides the acid environment in which pepsin is most effective. Rennin aids the digestion of milk proteins. Mucus secreted by the gastric glands helps protect the stomach lining from the action of gastric juice. Gastric secretion is stimulated by a number of hormones and chemical substances, by the presence of food in the stomach, and by a number of psychological factors, such as the smell of a favorite food. A decrease or total absence of gastric juice secretion may be a congenital abnormality or a concomitant of advanced age. Certain cells of the stomach lining secrete a substance known as intrinsic factor, which is necessary for the absorption of vitamin B12; absence of this substance results in pernicious anemia, or B12 deficiency (see vitaminvitamin,
group of organic substances that are required in the diet of humans and animals for normal growth, maintenance of life, and normal reproduction. Vitamins act as catalysts; very often either the vitamins themselves are coenzymes, or they form integral parts of coenzymes.
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).

Gastric Juice

 

a complex digestive juice secreted by various cells of the gastric mucosa; it is a colorless, slightly opalescent fluid. It contains the following enzymes: pro-teases (pepsins, rennin, gastricsin, and gelatinase), which accomplish the initial stages of protein decomposition; and a small quantity of lipase, which mainly decomposes emulsified fats. It also contains hydrochloric acid (concentration in humans is 0.4-0.5 percent) and mucus.

Hydrochloric acid activates enzymes and facilitates the decomposition of proteins, causing their denaturation and saturation; it conditions the bactericidal properties of gastric juice (inhibits the development of putrefactive processes in the stomach), and stimulates the secretion of gastric hormones. Hydrochloric acid in gastric juice is partly in a free state and partly bound (with proteins). The total acidity of gastric juice in man after a test breakfast is 40-60 conventional units; free acidity is 20-40 units. In some dysfunctions of the stomach, the hydrochloric-acid content of the gastric juice may increase or decrease to the point of complete absence (so-called achylia). Mucus, whose composition includes mucoproteins, protects the walls of the stomach from mechanical and chemical irritants. Gastric juice contains Castle’s intrinsic factor, which facilitates absorption of vitamin B12.

The secretion of gastric juice is determined in the first, compound-reflex phase of secretion by the appearance, odor, and taste of food; in the second, neurohumoral, phase, it is determined by chemical and mechanical stimuli to the gastric mucosa. Up to two liters of gastric juice is secreted by a human being every 24 hours. The quantity, composition, and properties of gastric juice vary according to the type of food in the stomach, and also when there are diseases of the stomach, intestine, or liver. Gastric juice is tested in humans by means of probing the stomach after the application of various natural and pharmacological stimuli; in animals it is tested by means of an artificially formed isolated stomach, according to a method perfected by I. P. Pavlov. Gastric juice obtained from animals is used internally in treating some diseases of the digestive organs.

V. G. KASSIL’ and IA. O. OL’SHANSKII

gastric juice

[′gas·trik ‚jüs]
(physiology)
The digestive fluid secreted by gastric glands; contains gastric acid and enzymes.

gastric juice

a digestive fluid secreted by the stomach, containing hydrochloric acid, pepsin, rennin, etc.
References in periodicals archive ?
However, the concentration of this VFA in the gastric juices evaluated was lower (0.
Gastric juice (1 ml) was taken in conical flask (100 ml) and diluted with distilled water (10 ml).
Studies of capsules solubility in gastric juice, and drug release rate showed that the formulation developed is optimal for manufacturing and storing capsules made of pharmaceutical gelatin vegetative analogues.
Figure 1 summarizes the results obtained from the digestive enzyme activity analyses in the hepatopancreas and the gastric juice of lobsters exposed to different nutritional conditions.
Destruction of the cells producing hydrochloric acid and intrinsic factor, respectively, results in hypochlorhydria and a reduction in pepsin activity within gastric juices and may lead to pernicious or iron deficiency anemia.
There are some contradictory opinions regarding the influence of gastric juice to the oncospheras.
After the surgery, the woman developed some complications; there was also a leakage of gastric juice that led to her death," he said.
The polymer is stable in saliva and specifically soluble in gastric juice.
After 4 h of surgery, rats were sacrificed and the gastric juice was collected for the estimation of free and total acids; mucin and peptic activity.
Several approaches were made to increase the gastric residence time of GRDF and majority of the work was carried out by employing low-density polymeric substances which can float in the gastric juice [5].
If there is a reduced secretion of gastric juice, the B-group vitamins do not stay in the organism for very long, including vitamin B12, the lack of which leads to anemia.
For example, he wanted to find out an important fact--does gastric juice dissolve the sutures holding the anastomosis together?