Regulation of Gastric Secretion MCQ Quiz | Gastrointestinal System

1. The cephalic phase of gastric secretion is primarily mediated by which of the following?

• A) Gastrin release from G-cells
• B) Vagal stimulation via the dorsal vagal complex
• C) The presence of amino acids in the stomach
• D) Release of secretin from the duodenum

2. Which hormone, secreted by G-cells in the stomach antrum, is the most potent stimulant of gastric acid secretion?

• A) Somatostatin
• B) Secretin
• C) Gastrin
• D) Cholecystokinin (CCK)

3. Somatostatin, released from D-cells, exerts its inhibitory effect on acid secretion primarily by:

• A) Directly inhibiting parietal cells and inhibiting gastrin release
• B) Stimulating mucus secretion
• C) Blocking H2 receptors on parietal cells
• D) Enhancing the enterogastric reflex

4. Zollinger-Ellison syndrome is characterized by hypersecretion of gastric acid due to a tumor secreting which hormone?

• A) Histamine
• B) Gastrin
• C) Acetylcholine
• D) Somatostatin

5. Histamine stimulates HCl secretion from parietal cells by binding to which type of receptor?

• A) H1 receptors
• B) H2 receptors
• C) Muscarinic M3 receptors
• D) CCK-B receptors

6. During the intestinal phase, the presence of acid in the duodenum triggers the release of which hormone that inhibits gastric acid secretion?

• A) Gastrin
• B) Motilin
• C) Secretin
• D) Vasoactive Intestinal Peptide (VIP)

7. A surgical vagotomy would most significantly reduce gastric acid secretion during which phase?

• A) Cephalic phase
• B) Gastric phase
• C) Intestinal phase
• D) Interdigestive phase

8. Proton Pump Inhibitors (PPIs) like omeprazole reduce gastric acid by directly blocking which of the following?

• A) H2 receptors
• B) Gastrin receptors
• C) H+/K+ ATPase pump on the parietal cell apical membrane
• D) Carbonic anhydrase enzyme

9. G-cells, responsible for gastrin secretion, are most concentrated in which region of the stomach?

• A) Cardia
• B) Fundus
• C) Body
• D) Antrum

10. Pepsinogen, the inactive precursor of pepsin, is secreted by which cells in the gastric glands?

• A) Parietal cells
• B) Chief cells
• C) G-cells
• D) Mucous neck cells

11. Intrinsic factor, secreted by parietal cells, is essential for the absorption of which vitamin in the terminal ileum?

• A) Vitamin C
• B) Vitamin K
• C) Vitamin B12 (Cobalamin)
• D) Folic acid

12. Enterochromaffin-like (ECL) cells are stimulated by gastrin to release which paracrine substance that acts on parietal cells?

• A) Somatostatin
• B) Acetylcholine
• C) Histamine
• D) Serotonin

13. The most powerful stimulus for the release of secretin from duodenal S-cells is:

• A) Presence of fats in the duodenum
• B) Presence of amino acids in the duodenum
• C) Acidic chyme (low pH) in the duodenum
• D) Duodenal distension

14. Which substance demonstrates a synergistic (potentiating) effect with acetylcholine and gastrin to maximally stimulate acid secretion from parietal cells?

• A) Prostaglandin E2
• B) Histamine
• C) Somatostatin
• D) Secretin

15. The gastric phase of acid secretion, which accounts for the majority of the response to a meal, is primarily initiated by:

• A) The sight and smell of foodB) Stomach distension and the presence of peptides
• C) Low pH in the duodenum
• D) The release of cholecystokinin (CCK)

16. Atropine, a muscarinic antagonist, reduces gastric acid secretion by blocking the action of which neurotransmitter on parietal cells?

• A) Gastrin
• B) Histamine
• C) Acetylcholine
• D) Norepinephrine

17. Which hormone is often referred to as “nature’s antacid” due to its potent, widespread inhibitory effects on gastrointestinal secretion and motility?

• A) Gastrin
• B) CCK
• C) Somatostatin
• D) GIP

18. Cholecystokinin (CCK), released in response to fats and proteins in the duodenum, primarily inhibits which gastric function?

• A) Gastric acid secretion
• B) Pepsinogen secretion
• C) Gastric emptying
• D) Mucus production

19. Chronic infection with Helicobacter pylori can lead to peptic ulcers by disrupting the mucosal barrier and causing hypergastrinemia, which is a result of:

• A) Directly stimulating G-cells
• B) Inhibiting somatostatin release from D-cells
• C) Increasing vagal tone
• D) Blocking secretin receptors

20. The majority of HCl-secreting parietal cells are located in which part of the stomach?

• A) Antrum and Pylorus
• B) Cardia
• C) Body and Fundus
• D) Pyloric sphincter

21. Gastric Inhibitory Peptide (GIP), now also known as glucose-dependent insulinotropic polypeptide, is released from the duodenum in response to:

• A) Acidic chyme
• B) Fat and glucose in the chyme
• C) Mechanical distension
• D) Vagal stimulation

22. The direct pathway of vagal stimulation of acid secretion involves the release of acetylcholine, which acts on which receptors on the parietal cell?

• A) Nicotinic receptors
• B) H2 receptors
• C) Muscarinic M3 receptors
• D) CCK-A receptors

23. The indirect pathway of vagal stimulation involves the release of Gastrin-Releasing Peptide (GRP) from vagal efferents, which stimulates:

• A) D-cells to release somatostatin
• B) G-cells to release gastrin
• C) Chief cells to release pepsinogen
• D) ECL cells to release histamine

24. Which of the following substances is NOT a direct stimulant of the parietal cell’s H+/K+ ATPase pump?

• A) Acetylcholine
• B) Histamine
• C) Gastrin
• D) Secretin

25. The enterogastric reflex, triggered by duodenal distension and irritation, is a:

• A) Hormonal reflex that stimulates gastric secretion
• B) Paracrine reflex involving histamine
• C) Neural reflex that inhibits gastric secretion and motility
• D) Myogenic reflex of the stomach smooth muscle