Topics:
Animal Physiology, Animal Refresher
Actions of Gastrin
Gastrin is secreted by G-cells of the stomach, which in turn stimulates-
- Parietal cells to secrete HCl & intrinsic factor (IF)
- Chief cells to secrete pepsinogen
- Both a & b — Correct Answer
- None of the above
Explanation:
Correct Answer: Both a & b
Gastrin (secreted by G-cells of stomach antrum) stimulates both types of gastric secretory cells simultaneously.
Gastrin's Two Target Cells
- Parietal cells (Oxyntic cells): Secrete HCl (gastric acid) + Intrinsic factor (IF). IF is essential for Vitamin B₁₂ absorption from ileum. IF deficiency → Pernicious anemia (macrocytic hyperchromic).
- Chief cells (Peptic/Zymogen cells): Secrete pepsinogen (inactive). HCl converts pepsinogen → active pepsin → protein digestion.
Gastric Secretion Cell Summary
- G-cells (antrum): Gastrin → stimulates HCl and pepsinogen secretion
- Parietal cells: HCl + Intrinsic factor (IF)
- Chief cells: Pepsinogen
- Mucous neck cells: Mucus (protects gastric epithelium from HCl)
In Ruminants
- Pepsinogen and HCl are secreted in ruminants by the Abomasum (true stomach)
Three Phases of Gastric Secretion
- Cephalic/Reflex → Gastric → Intestinal
- Cephalic phase is absent in herbivores
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
