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Gastric Glands and Gastric Juice
Concepts tested here
- Role of HCl in the stomach
All Questions
2008 AIPMT 1 question
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What will happen if the secretion of parietal cells of gastric glands is blocked with an inhibitor?The gastric glands have three major types of cells: mucus neck cells, peptic or chief cells, and parietal or oxyntic cells.
The parietal (oxyntic) cells secrete HCl and the intrinsic factor (essential for the absorption of vitamin B12).
The chief (peptic) cells secrete the proenzyme pepsinogen (and prorennin, the inactive form of chymosin, in infants).
The proenzyme pepsinogen, on exposure to hydrochloric acid, gets converted into the active enzyme pepsin. HCl also provides the acidic pH (about 1.8) that is optimal for pepsin.
If the secretion of the parietal cells is blocked, HCl will be absent, so pepsinogen will not be converted into active pepsin and protein digestion in the stomach will be affected.
Pepsinogen and chymosin are secreted by the chief cells, so the gastric juice will not be deficient in them, and enterokinase is secreted by the intestinal mucosa independently of the parietal cells.
So in the absence of HCl secretion, inactive pepsinogen is not converted into the active enzyme pepsin.