Deck 43: Digestion: Anatomy, Biochemistry, and Physiology

Question 1

A 57-year-old man is being examined by his physician due to complaints of frequent gnawing and burning pain in the middle and upper stomach occurring between meals and most acutely at night. Additional symptoms reported by the patient include heartburn, black stools, and on occasion seeing that his vomit looks like coffee grounds. You suspect the patient is suffering from a peptic ulcer. A defect in which of the following cells in the gastrointestinal tract would most likely be expected given this diagnosis?

A) chief
B) enterochromaffin-like (ECL)
C) enteroendocrine L cells
D) gastric mucus cells
E) parietal

Answer 1

parietal

Question 2

You are carrying out in vitro experiments that are designed to test the efficacy of novel compounds in the treatment of gastroesophageal reflux disease (GERD). You are testing the various compounds on gastric parietal cells in culture. You discover that one of the compounds exerts a significant inhibition of hydrogen ion (H+) secretion from the cells. This compound most likely mimics the effects of which of the following natural peptides?

A) cholecystokinin
B) gastrin
C) gastrin-releasing peptide
D) GLP-1
E) somatostatin

Answer 2

somatostatin

Question 3

You are tending to a 27-year-old woman whose chief complaint is that she can no longer taste sweetness in food, particularly fruits. You suspect that she may have a defect or disease of her tongue but physical examination as well as a small tissue biopsy show no anomalies. You order an assay of her saliva because you suspect she may have a defect in the secretion of which of the following enzymes?

A) a-amylase
B) haptocorrin
C) lingual lipase
D) lysozyme
E) mucin

Answer 3

a-amylase

Question 4

You are treating a 38-year-old man with complaints of near constant burning pain in his upper stomach which gets worse when he lies down at night. He informs you that his stools are black and that he frequently vomits up blood. You diagnose your patient as suffering from severe GI ulcerations and you suspect they are caused by Zollinger-Ellison syndrome. However, a gastric biopsy shows no apparent gastrinomas. Abnormal activity in the secretory function of which of the following cell types would most likely be associated with the symptoms in this patient?

A) chief
B) enterochromaffin-like (ECL)
C) enteroendocrine I
D) gastric mucus
E) parietal

Question 5

A 63-year-old man is being seen by his physician as a follow-up to gastric surgery for the treatment of a severe duodenal ulcers. This patient has the ulcers removed by surgical resection of the proximal portion of the duodenum to the distal end of the corpus of the stomach. The patient has been prescribed a proton pump inhibitor (PPI) because the surgery required removal of the region of the stomach that contains cells involved in the negative regulation of acid secretion. Which of the following represents these antrum located cells?

A) chief
B) D
C) enterochromaffin-like (ECL)
D) G
E) parietal

Question 6

Acetylcholine (ACh) directly stimulates parietal cell secretion of gastric acid by binding to muscarinic receptors of the M3 family present on these cells. Acetylcholine can also indirectly influence gastric acid secretion by activating M2 and M4 receptors present on which of the following cell types?

A) enterochromaffin-like (ECL)
B) enteroendocrine I
C) D
D) G
E) goblet

Question 7

A 45-year-old woman has come to her physician with complaints of abdominal pain, loss of appetite, fatigue, diarrhea, cramping, and bloating. Further history reveals that in addition to the frequent diarrhea, her stools are often bloody. Her physician suspects colitis and orders a colonoscopy which shows colonic mucosal erythema, ulcers, and bleeding. The symptoms of colitis seen in this patient are most likely due to a defect in the secretory properties of which of the following cell types?

A) chief
B) enterochromaffin-like (ECL)
C) enteroendocrine
D) goblet
E) parietal

Question 8

You are treating a 43-year-old woman who complains that her stools have recently acquired a foul smell and have an oily consistency. Ultrasonic examination reveals no apparent abnormalities in the gallbladder or pancreas. Biopsy of the main pancreatic duct also shows no overt pathology. Analysis of pancreatic juice isolated during the biopsy would most likely show a reduction or loss in the presence of which of the following enzymes, accounting for the change in stool in this patient?

A) a-amylase
B) carboxyl ester lipase
C) carboxypeptidase A
D) chymotrypsinogen
E) lipase

Question 9

As a physician on a mission to treat patients in subSaharan Africa you encounter numerous children with a common cluster of signs and symptoms. These include protuberant abdomens, generalized edema, loss of muscle mass, lethargy, irritability, and fatigue. Given the constellation of symptoms in your patients, your normal course of treatment would most likely include which of the following?

A) high concentration of total protein and/or essential amino acids
B) minimal amount of protein initially
C) only carbohydrates
D) only essential fatty acids
E) total caloric increase including protein, carbohydrate, and fat

Question 10

As a physician on a mission to treat patients in sub-Saharan Africa you encounter numerous children with a common cluster of signs and symptoms. These include chronic diarrhea, dizziness, fatigue, delayed wound healing, and muscle wasting. Given the constellation of symptoms in your patients, your normal course of treatment would most likely include which of the following?

A) high concentration of total protein and/or essential amino acids
B) minimal amount of protein initially
C) only carbohydrates
D) only essential fatty acids
E) total caloric increase including protein, carbohydrate, and fat

Question 11

You are studying the gastric secretions of a patient swith a rare form of nutritional malabsorption. You discover that the defect is due to a near complete loss of secretion of pepsinogen into the stomach in response to food intake. These observations could be explained by a defect in which type of gastrointestinal secretory cell?

A) chief
B) enteroendocrine I
C) enteroendocrine L
D) oxyntic
E) vagal nerve

Question 12

Which of the following hormones is responsible for the stimulation of bile secretions from the gallbladder?

A) cholecystokinin (CCK)
B) gastrin
C) gastrin-releasing hormone
D) glucagon-like peptide-1 (GLP-1)
E) protein tyrosine tyrosine (PYY)

Question 13

Which of the following statements relates to the role of salivary production of mucin?

A) activates lysozyme to initiate protein degradation
B) decreases the pH of the stomach contents to prevent excess denaturation of digestive enzymes
C) hydrolyzes complex carbohydrates so that they are substrates for salivary maltase
D) increases the pH of the saliva to denature proteins in the food
E) increases the viscosity of saliva to aid in swallowing

Question 14

A 14-year-old boy presents with weight loss and diarrhea. His tongue becomes sore and blistery after eating oatmeal or rye bread, which leads to the diagnosis of celiac disease. The boy and his parents are advised to be sensitive to symptoms of tetany and paresthesias since they can occur as a consequence of malabsorption of which of the following?

A) calcium
B) carbohydrates
C) fat
D) iron
E) water

Question 15

A patient presented with an acute abdomen including fever, marked abdominal distension, acidosis, and leukocytosis. Laparoscopy revealed that large parts of the small intestine were necrotic, and as a consequence the entire ileum of the patient was resected. It is expected that very soon after the surgery the patient will have considerable problems resulting from the malabsorption of which of the following?

A) bile acids
B) iron
C) protein
D) sodium
E) vitamin B₁₂

Question 16

You are examining digestive enzymes and their processes of activation. You have isolated a mutant form of one particular enzyme and find that it remains inactive in a mixture of digestive juices. The wild-type enzyme is normally activated by hydrolysis on the C-terminal side of Arg and Lys residues and you determine that the mutant enzyme contains Ser residues at these critical positions. Which of the following digestive enzymes is most likely responsible for activation of the wildtype enzyme in your studies?

A) aminopeptidase
B) carboxypeptidase
C) chymotrypsin
D) enteropeptidase
E) lysozyme

Question 17

A 54-year-old alcoholic man is admitted to the emergency room with an 8-hour history of severe epigastric pain. He reports that the pain radiates to his back and is more intense when he lies down. Physical examination reveals tachycardia, hypotension, and low-grade fever consistent with the early stage of shock. Which of the following serum measurements would be most useful in providing a diagnosis of his condition?

A) amylase
B) aspartate aminotransferase, AST
C) bilirubin
D) serum calcium
E) troponin I

Question 18

The manufacturer of energy bars makes claim that the fructose contained in their bars serves as an ideal source of energy for extreme mountain climbing and mountain biking expeditions. Which of the following statements concerning fructose reflects the basis for these claims?

A) absorption of fructose into an intestinal epithelial cell is by facilitated transport and thus does not require energy
B) metabolism of fructose generates more energy than glucose
C) some fructose is already absorbed in the mouth and hence is the fastest way to get energy
D) the presence of fructose aids in absorption of vitamin A, C, and D
E) the presence of fructose inhibits reabsorption of glucose, which is then more readily available for muscle activity

Question 19

Patients with functional dyspepsia and prominent nausea frequently experience spurts of excessive gastric acid exposure to the proximal duodenum. This results in increased pancreatic secretion, mainly through the action of which of the following substances?

A) cholecystokinin, CCK
B) gastrin
C) glucagon
D) secretin
E) vasoactive intestinal polypeptide, VIP

Question 20

You are examining a 33-year-old man whose chief complaints are that he has experienced recent weight loss and that he believes is due to the fact that he feels full after eating only a small amount of food. You determine that these symptoms are manifest due to a delay in the normal rate of gastric emptying. Given these findings, which of the following hormones is most likely to be excessively active in this patient?

A) cholecystokinin, CCK
B) gastrin
C) glucose-dependent insulinotropic peptide, GIP
D) motilin
E) pancreatic polypeptide, PP

Question 21

A healthy adult male of average size contains approximately 11 kg of total body protein. Approximately 5 kg of this is available as a source of energy primarily from skeletal muscle. Which of the following most closely represents the total caloric contribution of this protein source during prolonged fasting?

A) 1200 kcal
B) 22,000 kcal
C) 150,000 kcal
D) 400,000 kcal

Question 22

A 37-year-old man is being seen in the emergency room because of a 3-month history of nausea, vomiting, excessive thirst, increased urination, and generalized weakness. The patient has a 2-year history of gastric discomfort and pain which he has been attempting to manage with large quantities of antacids, a bland diet, and milk. Which of the following laboratory abnormalities is most likely in this patient?

A) decreased serum creatinine concentration
B) decreased serum phosphorous concentration
C) decreased serum urea nitrogen concentration
D) increased serum calcium concentration
E) metabolic acidosis

Question 23

Digestion of starch can occur even in the absence of pancreatic secretions. Which of the following digestive enzymes could best account for this?

A) biliary amylase
B) Brunner gland amylase
C) intestinal brush border amylase
D) intestinal brush border sucrase
E) salivary amylase

Question 24

Pancreatic amylase in the intestine cleaves starch primarily into which of the following?

A) disaccharides and trisaccharides of glucose
B) fucose monomers
C) fucose 1-phosphate
D) glucose 6-phosphate
E) linear polymers of glucose

Question 25

Which of the following best explains why adults are more likely than children to have gastrointestinal distress after consuming dairy products?

A) adults are more likely to be allergic to milk proteins
B) adults have lower activity of the enzyme that digests milk fats
C) adults have lower activity of the enzyme that digests milk proteins
D) adults have lower activity of the enzyme that digests milk sugar
E) adults secrete more gastric acid in response to dairy products