Vitamin B12 (cobalamin) absorption is dependent on intrinsic factor produced by which gastric cell?
- A Parietal (oxyntic) cells ✓
- B Chief (peptic) cells
- C G cells
- D D cells
Correct answer: A. Parietal (oxyntic) cells
Explanation
Intrinsic factor (IF) is a glycoprotein secreted by parietal cells in the gastric fundus and body, the same cells that secrete hydrochloric acid. IF binds cobalamin in the stomach and the IF-B12 complex is absorbed by specific receptors in the terminal ileum. Autoimmune destruction of parietal cells (atrophic gastritis with anti-parietal cell antibodies) leads to IF deficiency and pernicious anemia. Total gastrectomy also eliminates IF and causes B12 deficiency.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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