Pathology Parietal cells in the stomach secrete a protein crucial for the absorp on of vitamin B12 by the ileum. What is this protein? A Intrinsic factor B Gastrin C Somatostatin D Cholecystokinin (CCK) 💡 Explanation Parietal cells in the stomach secrete a protein crucial for the absorp on of vitamin B12 by the ileum. What is this protein? ✓ Correct Answer: A. Intrinsic factor