Gastrointestinal Physiology

Topics in this chapter

• Gastrointestinal Motility
• Gastric Acid and Secretion
• Pancreatic and Biliary Digestion
• Intestinal Digestion and Absorption
• Gastrointestinal Hormonal Regulation

Practice questions

1. Question 1Q-CE675A

   A 45-year-old man presents with chronic watery diarrhea, weight loss, and hypokalemia. Workup reveals a pancreatic neuroendocrine tumor. Basal gastric acid secretion is markedly elevated and refractory to standard medical therapy. Which of the following gastrointestinal hormones or peptides is most likely elevated in this patient?

   1. A.Gastrin
   2. B.Vasoactive Intestinal Peptide (VIP)
   3. C.Somatostatin
   4. D.Secretin
   See the answer and solution
2. Question 2Q-E40719

   During the interdigestive period, the gastrointestinal tract exhibits cyclical motor activity known as the Migrating Motor Complex (MMC). Which of the following phases of the MMC is characterized by the highest frequency of action potentials and intense, regular peristaltic contractions propagating down the small intestine?

   1. A.Phase I
   2. B.Phase II
   3. C.Phase III
   4. D.Phase IV
   See the answer and solution
3. Question 3Q-422144

   A 52-year-old woman undergoes total gastrectomy for gastric adenocarcinoma. Postoperatively, she is at high risk for developing macrocytic anemia due to a deficiency in which of the following substances normally secreted by the stomach?

   1. A.Hydrochloric acid
   2. B.Intrinsic factor
   3. C.Pepsinogen
   4. D.Gastrin
   See the answer and solution
4. Question 4Q-5979F1

   Fat digestion and absorption depend critically on the formation of micelles in the intestinal lumen. Which of the following components is primarily responsible for the hydrophilic outer shell of a mixed micelle?

   1. A.Triglycerides
   2. B.Cholesterol esters
   3. C.Bile salts
   4. D.Fat-soluble vitamins
   See the answer and solution
5. Question 5Q-AC101C

   Acid secretion by gastric parietal cells is stimulated by acetylcholine, histamine, and gastrin. Which of the following intracellular second messenger systems is primarily activated by histamine binding to its H2 receptor on the parietal cell?

   1. A.Phospholipase C / IP3 / Ca2+
   2. B.Adenylyl cyclase / cAMP
   3. C.Receptor tyrosine kinase
   4. D.cGMP pathway
   See the answer and solution