Gastrointestinal tract 2: the structure and function of the stomach

In this lesson, you will learn about the different juices that are secreted into the stomach and the role they play in digestion of your food. The release of histamine is the most important positive regulation mechanism of the secretion of gastric acid in the stomach.

Treat patients with dietary modification and pharmacological intervention. Dietary modification includes avoidance of acidic foods.

Further study showed that pepsin cleaved NAs in a moderately site-specific manner to yield 3′-phosphorylated fragments and the active site to digest NAs is probably the same as that used to digest protein. Our results rectify the misunderstandings that the digestion of NAs in the gastric tract begins in the intestine and that pepsin can only digest protein, shedding new light on NA metabolism and pepsin enzymology. A fluid secreted by glands lining the inside of the stomach. It contains hydrochloric acid and enzymes, such as pepsin, that aid in digestion. Too much or too little acid can cause problems.

All these drugs substantially inhibit acid secretion. Their chemical structures differ only minimally, and for practical purposes their pharmacology is identical. When acid secretion is stimulated with histamine, the systemic adverse effects of histamine can be prevented by a conventional antihistamine drug without affecting acid secretion.

Nursing Times events

Your doctor is the expert. It’s normal to have hydrochloric acid in the stomach, but In your case perhaps it’s affecting your mouth and nose. You need to ask your doctor for more information about your condition and about suggestions for treating the problem. If the stomach fluid contains a lot of acid, the natural sodium bicarbonate production in the organ may not be of much help.

Absence of free hydrochloric acid in gastric residue is considered abnormal only if the condition persists after maximal stimulation with pentagastrin (19). Anacidity is also associated with other clinical conditions, e.g., pernicious anemia and rheumatoid arthritis. In only ∼40% of patients with duodenal ulcer is the upper limit of the normal range of acidity exceeded. The use of gastric analysis decreased as more precise and informative diagnostic procedures became generally available, especially gastroscopy, improved roentgenographic techniques, exfoliative cytology, and newer laboratory procedures, such as gastrin by RIA (20).

Control of secretions

In hypochlorhydria and achlorhydria, there is low or no gastric acid in the stomach, potentially leading to problems as the disinfectant properties of the gastric lumen are decreased. In such conditions, there is greater risk of infections of the digestive tract (such as infection with Helicobacter or Vibrio bacteria (Vibrio is a genus of Gram-negative bacteria possessing a curved rod shape, several species of which can cause food borne infection, usually associated with eating undercooked seafood. Typically found in saltwater, Vibrio are facultative anaerobes that test positive for oxidase and do not form spores). Parietal cells within the stomach lining secrete hydrochloric acid that lower the pH of the stomach and activate pepsin.

A sphincter is a circular muscle that closes or opens the entrance or exit of a tubular structure. Under normal circumstances, the LES closes the entrance to the stomach once food has entered its lumen. If the LES doesn’t close or if it opens while food is still in the stomach, the churning, acidic mix in the stomach may be pushed up into the esophagus. The hydrochloric acid may then irritate the wall of the esophagus, producing pain and a condition known as heartburn.

(6, 29, 36). This enzyme has an α subunit, which contains the catalytic site of the enzyme (1), and a highly glycosylated β subunit (2, 25, 32, 34, 35). Gastric acid secretion is stimulated primarily by histamine released from enterochromaffin-like cells in response to gastrin (17). The functions outlined in the previous section are subserved by a number of products secreted by the stomach (Table 3-1).

in the human stomach lumen, the acidity being maintained by the proton pump H+/K+ ATPase. The parietal cell releases bicarbonate into the bloodstream in the process, which causes a temporary rise of pH in the blood, known as an alkaline tide.

Meals rich in protein and fat, such as a fried breakfast, tend to stay in the stomach for longer periods, while carbohydrate-rich foods, such as a baked potato or a piece of fruit, tend to pass through much faster (Kong and Singh, 2008; Gentilcore et al, 2006). The stomach, located in the upper left quadrant of the abdomen, is a J-shaped organ composed predominantly of involuntary smooth muscle.

Histamine H 2 -receptors are located on the basolateral membranes of the acid-secreting parietal cells in the stomach. They are activated by histamine derived from neighbouring mucosal cells. We now believe the main source of this histamine to be the principal endocrine cell of the gastric body or corpus – the enterochromaffin-like (ECL) cell. The ECL cells are mainly located in the lower part of the gastric glands, well-positioned to deliver their histamine into the capillaries which flow past them and the parietal cells (Fig. 1). One of the disadvantages of using animals to model human infections is the inherent difference between humans and the animals used.

name the acid present in gastric juice physiology degree

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