Proton-pump inhibitors affect which protective mechanism of the GI tract?

Proton-pump inhibitors affect which protective mechanism of the GI tract?

• A. Gastric acid
• B. Mucus
• C. IgA
• D. Bile

Answer: (A)

Proton-pump inhibitors block the final step of acid secretion in the stomach by inhibiting the H+/K+-ATPase proton pumps on parietal cells, greatly reducing gastric acidity. This lowered acidity is the protective mechanism most affected, because the acidic environment normally helps kill ingested pathogens and limit microbial growth in the upper GI tract. By raising the pH, PPIs weaken this barrier, which is why they’re linked to increased susceptibility to certain infections. The other options—mucus, IgA, and bile—are part of mucosal defense and digestion but are not directly reduced by PPIs, so they aren’t the primary mechanism affected.

Proton-pump inhibitors block the final step of acid secretion in the stomach by inhibiting the H+/K+-ATPase proton pumps on parietal cells, greatly reducing gastric acidity. This lowered acidity is the protective mechanism most affected, because the acidic environment normally helps kill ingested pathogens and limit microbial growth in the upper GI tract. By raising the pH, PPIs weaken this barrier, which is why they’re linked to increased susceptibility to certain infections. The other options—mucus, IgA, and bile—are part of mucosal defense and digestion but are not directly reduced by PPIs, so they aren’t the primary mechanism affected.