Which of the following causes relaxation of the lower esophageal sphincter (LES) in response to swallowing?
a. Circulating gastrin
b. Inhibitory sympathetic nerve input to the LES
c. Intrinsic myogenic tone of circular smooth muscle
d. Release of acetylcholine from the myenteric plexus
e. Release of vasoactive intestinal peptide and nitric oxide from inhibitory ganglionic neurons
311. A 52-year-old man with diabetes mellitus type 1 has persistent nausea and vomiting due to gastroparesis with gastroesophageal reflux disease (GERD). Which of the following best describes the function of gastric emptying?
a. Acidification of the antrum increases gastric emptying.
b. Hyperosmolality of duodenal contents initiates a decrease in gastric emptying.
c. Meals containing fat empty faster than carbohydrate-rich food.
d. Solids empty more rapidly than liquids.
e. Vagal stimulation decreases receptive relaxation in the upper portion of the stomach.
312. A 27-year-old female medical student with irritable bowel syndrome (IBS) has an alteration in intestinal motility resulting in fluctuating constipation and diarrhea. Her condition has worsened in the last month as the date she has scheduled for her licensure examination approaches. Which of the following best describes small intestinal motility?
a. Contractile activity is initiated in response to bowel wall distention.
b. Contractile frequency is constant from duodenum to terminal ileum.
c. Migrating motor complexes (MMCs) occur during the digestive period.
d. Peristalsis is the only contractile activity that occurs during feeding.
e. Vagotomy abolishes contractile activity during the digestive period.
313. An 18-year-old man with pernicious anemia lacks intrinsic factor, which is necessary for the absorption of cyanocobalamin. Vitamin B12 is absorbed primarily in which portion of the gastrointestinal (GI) tract?
314. A 27-year-old woman comes to the emergency room because of a 2-day bout of profuse watery diarrhea. Physical examination reveals dry lips and oropharynx. The patient is diagnosed with acute secretory diarrhea and dehydration, likely due to Escherichia coli. Which of the following sodium reabsorptive pathways is inhibited by the enterotoxin?
a. Electroneutral NaCl transport
b. Sodium–bile salt cotransport
c. Sodium–glucose coupled cotransport
d. Sodium–hydrogen countertransport
e. Sodium–phosphorous countertransport
315. A 37-year-old man presents with dehydration and hypokalemic metabolic acidosis. This acid–base and electrolyte disorder can occur with excess fluid loss from which of the following organs?
316. A 35-year-old male smoker presents with burning epigastric pain that is most pronounced on an empty stomach. In addition to peptic ulcer disease and gastric acid hypersecretion, the patient has a paroxysmal rise in serum gastrin in response to intravenous (IV) secretin. Normally, basal acid output is increased by which of the following?
a. Acidification of the antrum
b. Acidification of the duodenum
c. Administration of an H2-receptor antagonist
d. Alkalinization of the antrum
317. A 42-year-old man develops a gastric carcinoma affecting the proximal third of his stomach. He is scheduled for a partial gastrectomy of the affected region. Which of the following processes will be most affected by the surgery?
a. Receptive relaxation
318. A 37-year-old man with AIDS presents with a fever, anorexia, weight loss, and GI bleeding. Physical examination reveals a palpable abdominal mass. Endoscopy and biopsy reveal a proximal small-bowel malignancy requiring surgical resection. Removal of proximal segments of the small intestine would most likely result in a decrease in which of the following?
a. Basal acid output
b. Maximal acid output
c. Gastric emptying of liquids
d. Gastric emptying of solids
e. Pancreatic enzyme secretion
319. A 63-year-old woman has an intractable duodenal ulcer failing all previous treatments. After consultation with a surgeon, a laparoscopic vagotomy is performed. Subsequently, the patient experiences nausea and vomiting after ingestion of a mixed meal. Which of the following best explains her symptoms?
a. Decreased gastric emptying of liquids
b. Decreased gastric emptying of solids
c. Increased gastric emptying of liquids
d. Increased gastric emptying of solids
e. Increased gastric emptying of solids and liquids
320. A 17-year-old adolescent boy who is being treated with the macro-lide antibiotic erythromycin complains of nausea, intestinal cramping, and diarrhea. The side effects are the result of the antibiotic binding to receptors in the GI tract that recognize which GI hormone?
321. A 23-year-old woman complains of abdominal cramps and bloating that are relieved by defecation. Subsequent clinical evaluation reveals an increased maximal acid output, decreased serum calcium and iron concentrations, and microcytic anemia. Inflammation in which area of the GI tract best explains these findings?
322. A 57-year-old woman undergoes resection of the terminal ileum as part of treatment for her chronic inflammatory bowel disease. Removal of the terminal ileum will most likely result in which of the following?
a. Decreased glucose absorption
b. Decreased water content of the feces
c. Increased bile acid concentration in the enterohepatic circulation
d. Increased excretion of fatty acids
e. Increased iron absorption
323. A 67-year-old man with a history of alcohol abuse presents to the emergency room with severe epigastric pain, hypotension, abdominal distension, and diarrhea with steatorrhea. Serum amylase and lipase are found to be greater than normal, leading to a diagnosis of pancreatitis. The steatorrhea can be accounted for by a decrease in the intraluminal concentration of which of the following pancreatic enzymes?
324. After a recent viral illness, a 20-year-old woman develops bilateral facial swelling consistent with parotitis. Which of the following best describes the salivary glands?
a. Approximately 4 L of saliva is secreted per day.
b. Salivary α-amylase preferentially hydrolyzes 1:6α over 1:4α linkages.
c. Cranial nerve VIII passes through the parotid gland.
d. Starch digestion begins in the mouth via salivary α-amylase.
e. The parotid gland is the most mucinous of the salivary glands.
325. A newborn with severe diarrhea is found to have an inherited defect in a glucose transporter resulting in glucose/galactose malabsorption, necessitating a glucose- and galactose-free diet. Which of the following is the transport protein responsible for entry of glucose into the intestinal enterocyte?
c. SGLT 1
d. SGLT 2
e. SGLT 5
326. A 43-year-old woman presents with dysphagia to solids and liquids, bland regurgitation, and diffuse chest pain of 2 months duration. During this time, she has lost about 20 pounds. The patient is scheduled for esophageal imaging and motility testing. The esophagogram during a barium swallow shows a dilated esophagus with an area of distal stenosis and esophageal manometry tracings during a wet swallow shows a high lower esophageal sphincter (LES) opening pressure and uncoordinated peristalsis.
These findings are consistent with which of the following diagnoses?
b. Diffuse esophageal spasm
d. Schatzki ring
e. Zenker diverticulum
327. A 42-year-old salesman presents with the chief complaint of intermittent midepigastric pain that is relieved by antacids or eating. Gastric analysis reveals that basal and maximal acid outputs exceed normal values. The gastric acid hypersecretion can be explained by an increase in the plasma concentration of which of the following?
e. Vasoactive intestinal peptide
328. A 70-year-old woman presents with abdominal pain, microcytic anemia, and weight loss. Colonoscopy with biopsy confirms colon cancer. Which of the following best describes colonic function?
a. Absorption of Na+ in the colon is under hormonal control by aldosterone.
b. Bile acids enhance absorption of water from the colon.
c. Net absorption of occurs in the colon.
d. Net absorption of K+ occurs in the colon.
e. The luminal potential in the colon is positive.
329. A 42-year-old woman presents to the emergency room with right upper quadrant pain that developed after eating dinner. She is diagnosed as having cholecystitis. Which of the following would be expected with contraction of the gallbladder following a meal?
a. It is inhibited by a fat-rich meal.
b. It is inhibited by the presence of amino acids in the duodenum.
c. It is stimulated by atropine.
d. It occurs in response to cholecystokinin.
e. It occurs simultaneously with the contraction of the sphincter of Oddi.
330. A 42-year-old airline pilot presents to his family physician with a chief complaint of midepigastric pain that is relieved by antacids or eating. Endoscopic evaluation reveals the presence of a duodenal ulcer. Based on the diagnosis, which of the following also would be expected?
a. Decreased basal acid output
b. Decreased gastric emptying of liquids
c. Decreased gastric emptying of solids
d. Increased bicarbonate secretion in the duodenal bulb
e. Increased maximal acid output
331. A 43-year-old woman presents with chief complaints of bulky and frequent diarrhea and weight loss. She experiences recurrent episodes of abdominal distension terminated by passage of stools. Laboratory data reveals a microcytic anemia, decreased serum calcium, and decreased serum albumin. Her generalized decrease in intestinal absorption can be attributed to which of the following?
a. Decreased gastric emptying
b. Decreased intestinal motility
c. Decreased intestinal surface area
d. Increased enterohepatic circulation of bile
e. Increased migrating motor complexes
332. A 68-year-old woman with rheumatoid arthritis, who has been taking nonsteroidal anti-inflammatory drugs (NSAIDs) for the past 10 years, complains of burning epigastric pain that is relieved by antacids, but worsened with food. Her doctor discontinues the NSAIDs and recommends cimeti-dine (Tagamet) because it is inexpensive and over the counter. Which of the following best describes the pharmacological blockade of histamine H2 receptors in the gastric mucosa?
a. It inhibits both gastrin-and acetylcholine-mediated secretion of acid.
b. It inhibits gastrin-induced but not meal-stimulated secretion of acid.
c. It has no effect on either gastrin-induced or meal-stimulated secretion of acid.
d. It prevents activation of adenyl cyclase by gastrin.
e. It causes an increase in potassium transport by gastric parietal cells.
333. A 37-year-old man is admitted to the hospital due to an exacerbation of his Crohn’s disease with severe inflammation of the ileum. Which of the following would be seen?
a. Decreased bile acid pool size
b. Decreased release of secretin
c. Increased absorption of dietary fats
d. Increased colon absorption of water
e. Increased vitamin B12 absorption
334. A 47-year-old man takes esomeprazole for his “acid indigestion.” Which of the following best describes the use of substituted benzimidazole derivatives?
a. They are not effective as part of a treatment regimen for Helicobacter pylori.
b. They are not used in the treatment of Zollinger–Ellison syndrome.
c. They are water-soluble compounds.
d. They decrease gastrin levels.
e. They inhibit H–K-ATPase in parietal cells.
335. A 57-year-old man undergoes resection of the distal 100 cm of the terminal ileum as part of treatment for Crohn’s disease. The patient likely will develop malabsorption of which of the following?
a. Bile salts
336. A 62-year-old woman is prescribed the prostaglandin E agonist, misoprostol, along with a NSAID for her severe bilateral osteoarthritis of the knees. What is the purpose of the misoprostol?
a. Antagonizes H2 receptors
b. Enhances LES relaxation, thereby preventing NSAID-induced dysphagia
c. Increases colonic water reabsorption, thereby preventing diarrhea
d. Inhibits bicarbonate secretion into the gastric mucous gel
e. Prevents NSAID-induced gastric ulcers
337. An 18-year-old college student reports that she experiences severe abdominal bloating and diarrhea within 1 hour of consuming dairy products. A subsequent hydrogen breath test is abnormal. The diarrhea and bloating can best be explained by which of the following?
a. A decrease in exocrine pancreatic secretion
b. A deficiency in the brush border enzyme lactase
c. Carbohydrate-induced secretory diarrhea
d. Decreased carbohydrate absorption
e. Decreased intestinal surface area
338. A 32-year-old woman presents to the emergency department with abdominal pain and diarrhea accompanied by steatorrhea. Gastric analysis reveals a basal acid output of 12 mmol/hour (normal: <5 mmol/hour). The steatorrhea is most likely due to which of the following?
a. Decreased gastric acid secretion
b. Decreased pyloric sphincter tone
c. Decreased secretion of intrinsic factor
d. Delayed gastric emptying
e. Inactivation of pancreatic lipase due to low duodenal pH
339. A 42-year-old obese woman presents to the emergency department with right upper quadrant pain, nausea, and vomiting. The pain is not related to food intake and lasts for several hours before resolving slowly. Ultrasound images are suggestive of gallstones with cystic duct obstruction. Which of the following is the primary physiological stimulus of gall-bladder contraction in the digestive period?
a. Acid-induced release of motilin from the small intestine
b. Acid-induced release of secretin from the small intestine
c. Amino acid-induced release of motilin from the small intestine
d. Distension-induced release of glucagon from the small intestine
e. Fat-induced release of cholecystokinin from the small intestine
340. A 20-year-old woman with type 1 diabetes mellitus presents with symptomatic hyperglycemia. The patient is started on insulin. The metabolic effects of insulin include which of the following?
a. Decreased glucose utilization
b. Decreased lipolysis
c. Increased proteolysis
d. Increased gluconeogenesis
e. Increased ketogenesis
341. A 31-year-old man presents to the emergency department with the symptoms of heartburn and difficulty swallowing. Esophageal manometry reveals an inflamed esophageal mucosa and a hypotensive LES. A diagnosis of GERD is made and the patient is subsequently treated with a proton pump inhibitor. Normally, which of the following is most likely regarding reflux of gastric acid into the esophagus?
a. It inhibits esophageal bicarbonate secretion.
b. It inhibits gastric acid secretion.
c. It inhibits gastric motility.
d. It initiates primary esophageal peristalsis.
e. It initiates secondary esophageal peristalsis.
342. A 56-year-old man presents with postprandial diarrhea persisting since an ileal resection. The gastric surgeon suspects bile acid malabsorption. Which of the following best describes bile acid function?
a. They are essentially water insoluble.
b. The majority of bile acids are absorbed by passive diffusion.
c. Glycine conjugates are more soluble than taurine conjugates.
d. The amount lost in the stool each day represents the daily loss of cholesterol.
e. The bile acid–dependent fraction of bile is stimulated by the hormone secretin.
343. A 26-year-old man presents to the emergency room with a 48-hour bout of diarrhea with steatorrhea. Which of the following best accounts for the appearance of excess fat in the stool?
a. Decreased bile acid pool size
b. Increased bile salt reabsorption
c. Increased colonic microbiota
d. Increased chylomicron formation
e. Increased lipase secretion
344. A 14-year-old ballerina reports that she has chronic diarrhea. A detailed history reveals that she frequently drinks skim milk, she does not use laxatives, and she has noticed that her condition improves when she fasts for religious observances. In contrast to secretory diarrhea, which of the following is most likely seen with osmotic diarrhea?
a. It is caused by bacterial toxins.
b. It is characterized by an increase in the stool osmotic gap.
c. It is the result of decreased electroneutral sodium absorption.
d. It is the result of increased crypt cell secretion.
e. It occurs only in the colon.
345. An 83-year-old woman with constipation is prescribed a high-fiber diet, which leads to an increased production of short-chain fatty acids (SCFAs). SCFA absorption occurs almost exclusively from which of the following segments of the GI tract?
346. A 42-year-old man presents to the emergency room with epigastric abdominal pain associated with nausea and vomiting. The history reveals that he was binge drinking that evening. He is diagnosed with acute pancreatitis. Which of the following best describes pancreatic function in this patient?
a. Pancreatic lipase converts triglycerides into fatty acids and glycerol.
b. Phospholipase A2 may be prematurely activated by trypsin.
c. Secretin inhibits secretion from the pancreas.
d. Serum amylase would be decreased in this patient.
e. Serum lipase would be decreased in this patient.
347. A 47-year-old woman with hypermenorrhea develops an iron-deficiency anemia requiring iron supplements. Which of the following best describes iron digestion and absorption?
a. About 100 mg of iron is absorbed per day.
b. Iron is absorbed rapidly from the small intestine.
c. Iron is transported into enterocytes by a ferroportin transporter on the apical membrane.
d. Iron is transported in the blood bound to transferrin.
e. Iron is oxidized from the ferrous to the ferric state during absorption.
348. A patient with alcoholic cirrhosis presents to the emergency room with hematemesis. After stabilizing him with IV fluids, the gastroenterolo-gist administers an analog of which of the following agents to inhibit gastric acid secretion and visceral blood flow?
349. A patient has vomiting and severe watery diarrhea after eating spoiled shellfish. IV fluid and electrolyte replacement was started, and a stool specimen was taken, which came back positive for Vibrio cholerae. Which of the following statements best describes water and electrolyte absorption in the GI tract?
a. Electrolyte absorption in the small intestine is primarily electrogenic.
b. Osmotic equilibration of chyme occurs in the ileum.
c. The majority of water and electrolyte absorption occurs in the jejunum.
d. The small intestine and colon have similar absorptive capacities.
e. The toxin produced by V. cholerae decreases cyclic AMP in intestinal epithelial cells.
350. A 38-year-old man has dinner one evening at his favorite steakhouse. Several hours later, the chyme reaches the duodenum. After secretion of trypsinogen into the duodenum, the enzyme is converted into its active form, trypsin, by which of the following?
a. Alkaline pH
d. Pancreatic lipase
351. An 18-year-old woman decides to get a tattoo for her birthday. Two months later she presents with a fever, right upper quadrant pain, nausea, vomiting, and jaundice. Which of the following laboratory values would most likely be found in a patient with infectious hepatitis?
a. A decrease in both direct and indirect plasma bilirubin
b. A decrease in plasma alkaline phosphatase
c. An increase in both direct and indirect plasma bilirubin
d. An increase in plasma alkaline phosphatase
e. An increase in plasma bile acids
352. A 27-year-old female patient with a history of IBS presents with a chief complaint of flatulence. Gas within the colon is primarily derived from which of the following sources?
a. Air pockets in diverticula
b. CO2 liberated by the interaction of and H+
c. Diffusion from the blood
d. Fermentation of undigested oligosaccharides
e. Swallowed atmospheric air
353. A 60-year-old woman presents to her family physician with complaints of paresthesias in her lower legs bilaterally. On physical examination she is found to have a shiny tongue. During the workup, a complete blood count reveals a macrocytic anemia with hypersegmented neutrophils on peripheral smear. She is subsequently diagnosed with pernicious anemia. With respect to cobalamin-intrinsic factor binding in a normal individual, nearly all binding of cobalamin to intrinsic factor occurs in which of the following organs?
354. A 29-year-old internal medicine resident has a breakfast buffet after a long night of call. The rate of gastric emptying increases with an increase in which of the following?
a. Acidity of duodenum
b. Fat content of duodenum
c. Intraduodenal volume
d. Intragastric volume
e. Osmolality of duodenum
355. A 52-year-old woman who has been dieting for several weeks breaks down and eats half a pan of frosted brownies. Insulin secretion following a carbohydrate-rich meal is stimulated by which of the following?
c. Glucagon-like polypeptide 1 (GLP-1)
356. A 53-year-old man presents with a chronic cough. The history and physical findings rule out postnasal drip, asthma, and other pulmonary disease. Upon questioning, the patient also reports substernal burning pain that is most pronounced after ingestion of coffee, chocolate, french fries, and alcohol. Which of the following is the most likely cause of the symptoms in this patient?
a. Decreased esophageal motility
b. Decreased LES tone
c. Decreased upper esophageal sphincter tone
d. Delayed gastric emptying
e. Hiatal hernia
357. A new mother calls the pediatrician because she is concerned that her infant defecates after every meal. Which of the following is the cause of normal bowel movements in newborns?
a. Defecation reflex
b. Gastrocolic reflex
c. Gastroileal reflex
d. Intestinointestinal reflex
e. Peristaltic rushes
358. A 10-year-old boy presents with below-average body weight and height, signs of vitamin K deficiency, steatorrhea, and bloating. He is found to have the MHC class II antigen HLA-DQ2. Which of the following is the most appropriate dietary treatment for malabsorption in this condition?
a. Fat-free diet
b. Gluten-free diet
c. High-fiber diet
d. Lactose-free diet
e. Low-salt diet
359. A 47-year-old woman presents to her primary care physician with jaundice. She is found to have elevated levels of direct (conjugated) plasma bilirubin. Which of the following is the most likely diagnosis?
a. Crigler–Najjar syndrome type I
b. Crigler–Najjar syndrome type II
c. Gilbert syndrome
d. Hemolytic anemia
e. Obstruction of the common bile duct
360. A morbidly obese man presents with hypertension, hyperlipidemia, and type 2 diabetes mellitus. Dietary fat, after being processed, is extruded from the mucosal cells of the GI tract into the lymphatic ducts in the form of which of the following?
b. Free fatty acids
361. After a long workout, a third-year medical student drinks a bottle of an electrolyte-containing sports drink. Which of the following is the major mechanism for absorption of sodium from the small intestine?
a. Cotransport with
b. Electrogenic transport
c. Na+–K+ exchange
d. Neutral NaCl absorption
e. Solvent drag
362. A 42-year-old healthy man takes a daily multivitamin to complement his diet. Which of the following is required for absorption of the fat-soluble vitamins contained in his supplement?
b. Intrinsic factor
c. Pancreatic amylase
d. Pancreatic lipase
363. Following gastric bypass surgery, a patient presents with crampy abdominal discomfort 15 to 30 minutes after meals, accompanied by nausea, diarrhea, belching, tachycardia, palpitations, diaphoresis, and light-headedness. These symptoms most likely arise from which of the following?
a. Decreased emptying of hyperosmotic gastric contents
b. Decreased insulin release
d. Increased secretion of cholecystokinin
e. Release of VIP and motilin
364. A 61-year-old woman presents with diarrhea, abdominal pain, and flushing. Urinary excretion of the serotonin metabolite, 5-hydroxyindoleacetic acid, is elevated. Abdominal CT reveals a tumor in the terminal ileum. Surgical resection of the terminal ileum will most likely result in which of the following?
a. A decrease in absorption of amino acids
b. A decrease in the fat content of the feces
c. An increase in the absorption of iron
d. An increase in the concentration of bile acid in the enterohepatic circulation
e. An increase in the water content of the feces
365. Twenty years ago, a 65-year-old man underwent vagotomy for his refractory peptic ulcer disease. As a result, which of the following GI motor activities will be affected most?
a. Distention-induced intestinal segmentation
b. Migrating motor complexes
c. Orad stomach accommodation
d. Secondary esophageal peristalsis
366. A 33-year-old woman who has been taking large doses of NSAIDs for her menstrual cramps presents with burning epigastric pain that is worse after eating. Which of the following is the major factor that protects the duodenal mucosa from damage by gastric acid?
a. Bicarbonate contained in bile
b. Duodenal bicarbonate secretion
c. Endogenous mucosal barrier of the duodenum
d. Hepatic bicarbonate secretion
e. Pancreatic bicarbonate secretion
367. Gastric emptying studies performed on a 49-year-old woman who has vomiting shortly after eating reveal a normal rate of liquid emptying, but a prolonged time for emptying of solids. Which of the following best explains these findings?
a. Colonic obstruction
b. Increased amplitude of antral contractions
c. Inflammation of the proximal small intestine
d. Pyloric stenosis
e. Sectioning of the vagus nerves to the stomach
368. A full-term newborn infant with abdominal distention has not had a bowel movement for 5 days. An x-ray of the abdomen shows a narrowed colon, bowel obstruction, and dilated intestine above the obstruction. A suction rectal biopsy is done at the bedside. The pathology report indicates the absence of ganglion cells and the presence of nonmyelinated nerves in the biopsy segment. What is the underlying cause of the bowel obstruction in this patient?
a. Activation of intestinal opioid receptors
b. Carcinoid tumor
c. Impaired endothelin B receptor function
d. Impaired gastrocolic reflex
e. Increased activity of splanchnic sympathetic nerves
369. In the light microscopic slide shown below obtained from a biopsy of the stomach, which of the following is secreted by the cell type identified by the arrows?