Question 5#

Which of the following is secreted by gastric parietal cells?

A. Pepsinogen
B. Intrinsic factor
C. Gastrin-releasing peptide
D. Ghrelin
E. Histamine

Correct Answer is B


Activated parietal cells secrete intrinsic factor in addition to hydrochloric acid. Presumably the stimulants are similar, but acid secretion and intrinsic factor secretion may not be linked. Intrinsic factor binds to luminal vitamin B12, and the complex is absorbed in the terminal ileum via mucosal receptors. Vitamin B 12 deficiency can be life-threatening, and patients with total gastrectomy or pernicious anemia require B12 supplementation by a nonenteric route.