Question

If for some reason the parietal cells of the stomach epithelium become partially non-functional, what is likely to happen?
A. Proteins will not be adequately hydrolyzed by pepsin into proteases and peptones.
B. The pancreatic enzymes and especially the trypsin and lipase will not work efficiently.
C. The pH of the stomach will fall abruptly.
D. Steapsin will be more effective.

Answer 1

Parietal cells are found in the stomach. These cells produce HCl and Castle Intrinsic Factor. HCl maintains the pH of the stomach. It also helps in the digestion of the proteins of the food by activating the necessary enzymes.

Complete answer: The parietal cells are also known as the oxyntic cells. Sometimes, they are also referred to as the delomorphous cells. These cells are found in the lamina propria layer of the mucosa wall of the fundic part of the stomach epithelium. The parietal cells are responsible for producing the hydrochloric acid and the castle intrinsic factor. Hydrochloric acid is an important constituent of gastric juice. It makes the medium acidic and maintains a pH of $1.5$ to $3$. It does not let the germs and the bacteria to thrive in the environment of the stomach. Moreover, the hydrochloric acid activates the pepsinogen enzyme of the gastric juice. It converts the pepsinogen into the pepsin. This pepsin is the main proteolytic enzyme in the stomach. This means that it causes the lysis or the breaking of the proteins in the stomach. The proteins are hydrolyzed into proteases and peptones. Also, hydrochloric acid helps to dissolve or break the hard substances. They also dissolve the nucleoproteins. Lastly, the hydrochloric acid regulates the opening and closing of the pyloric sphincter.
Thus, based on the above information we can conclude that if for some reason the parietal cells of the stomach epithelium become partially non-functional then the Proteins will not be adequately hydrolyzed by pepsin into proteases and peptones.
Hence, the correct answer is option (A).

Note: The castle intrinsic factor helps in the absorption of Vitamin B12. Vitamin B12 is also known as cobalamin. Its deficiency causes pernicious anemia. The castle intrinsic factor forms in the stomach but works in the ileum of the small intestine.