The Physiology of Gastric Secretions - last part
February 4th 2010 16:36
Pepsinogen
Pepsinogen release is dependent on the acetylcholine stimulation of the peptic cells, and the presence of hydrochloric acid in the stomach. Pepsinogen per se has no digestive function. When it comes in contact with previously formed pepsin and hydrochloric acid, it is activated as pepsin. Pepsin is as necessary as hydrochloric acid for protein digestion in the stomach.
The proteolytic activity of pepsin takes place in an acidic setting (optimum pH of 1.8 to 3.5). Above 5, pepsin has almost no activity.
Acid-Peptic Disorder
The pathology of acid-peptic disorder lies behind the imbalance between the rate of secretion of gastric juice and the degree of protection provided by the mucosal barrier and neutralization of gastric juice by pancreatic secretions. The scenario can be caused by Helicobacter pylori infecting the gastrointestinal tract and hypersecretion of acid-peptic complex. Smoking can also increase nervous stimulation of the stomach secretory glands. Alcohol and aspirin in turn breaks the mucosal barrier. Caffeine also increases gastric acidity.
Caffeine inhibits phosphodiesterase thus increasing cAMP within cells. In the parietal cells, this will mean a stimulation of gastric juice secretion. Aspirin and other non-selective anti-inflammatory drugs inhibt COX1, which generates prostanoid for epithelial cytoprotection.
Pepsinogen release is dependent on the acetylcholine stimulation of the peptic cells, and the presence of hydrochloric acid in the stomach. Pepsinogen per se has no digestive function. When it comes in contact with previously formed pepsin and hydrochloric acid, it is activated as pepsin. Pepsin is as necessary as hydrochloric acid for protein digestion in the stomach.
The proteolytic activity of pepsin takes place in an acidic setting (optimum pH of 1.8 to 3.5). Above 5, pepsin has almost no activity.
Acid-Peptic Disorder
The pathology of acid-peptic disorder lies behind the imbalance between the rate of secretion of gastric juice and the degree of protection provided by the mucosal barrier and neutralization of gastric juice by pancreatic secretions. The scenario can be caused by Helicobacter pylori infecting the gastrointestinal tract and hypersecretion of acid-peptic complex. Smoking can also increase nervous stimulation of the stomach secretory glands. Alcohol and aspirin in turn breaks the mucosal barrier. Caffeine also increases gastric acidity.
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