Deck 6: Gastrointestinal Physiology

Question 1

Which of the following substances is released from neurons in the GI tract and produces smooth muscle relaxation?

A) Secretin
B) Gastrin
C) Cholecystokinin (CCK)
D) Vasoactive intestinal peptide (VIP)
E) Gastric inhibitory peptide (GIP)

Answer 1

Vasoactive intestinal peptide (VIP)

Question 2

Which of the following is the site of secretion of intrinsic factor?

A) Gastric antrum
B) Gastric fundus
C) Duodenum
D) Ileum
E) Colon

Answer 2

Gastric fundus

Question 3

Vibrio cholerae causes diarrhea because it

A) increases $\mathrm{HCO}_{3}{ }^{-}$ secretory channels in intestinal epithelial cells
B) increases $\mathrm{Cl}^{-}$ secretory channels in crypt cells
C) prevents the absorption of glucose and causes water to be retained in the intestinal lumen isosmotically
D) inhibits cyclic adenosine monophosphate (cAMP) production in intestinal epithelial cells
E) inhibits inositol 1,4,5-triphosphate $\left(\mathrm{IP}_{3}\right)$ production in intestinal epithelial cells

Answer 3

increases $\mathrm{Cl}^{-}$ secretory channels in crypt cells

Question 4

Cholecystokinin (CCK) has some gastrinlike properties because both CCK and gastrin

A) are released from $\mathrm{G}$ cells in the stomach
B) are released from I cells in the duodenum
C) are members of the secretin-homologous family
D) have five identical C-terminal amino acids
E) have $90 \%$ homology of their amino acids

Question 5

Which of the following is transported in intestinal epithelial cells by a $\mathrm{Na}^{+}$ -dependent cotransport process?

A) Fatty acids
B) Triglycerides
C) Fructose
D) Alanine
E) Oligopeptides

Question 6

A 49-year-old male patient with severe Crohn disease has been unresponsive to drug therapy and undergoes ileal resection. After the surgery, he will have steatorrhea because

A) the liver bile acid pool increases
B) chylomicrons do not form in the intestinal lumen
C) micelles do not form in the intestinal lumen
D) dietary triglycerides cannot be digested
E) the pancreas does not secrete lipase

Question 7

Cholecystokinin (CCK) inhibits

A) gastric emptying
B) pancreatic $\mathrm{HCO}_{3}^{-}$ secretion
C) pancreatic enzyme secretion
D) contraction of the gallbladder
E) relaxation of the sphincter of Oddi

Question 8

Which of the following abolishes "receptive relaxation" of the stomach?

A) Parasympathetic stimulation
B) Sympathetic stimulation
C) Vagotomy
D) Administration of gastrin
E) Administration of vasoactive intestinal peptide (VIP)
F) Administration of cholecystokinin (CCK)

Question 9

Secretion of which of the following substances is inhibited by low $\mathrm{pH}$ ?

A) Secretin
B) Gastrin
C) Cholecystokinin (CCK)
D) Vasoactive intestinal peptide (VIP)
E) Gastric inhibitory peptide (GIP)

Question 10

Which of the following is the site of secretion of gastrin?

A) Gastric antrum
B) Gastric fundus
C) Duodenum
D) Ileum
E) Colon

Question 11

Micelle formation is necessary for the intestinal absorption of

A) glycerol
B) galactose
C) leucine
D) bile acids
E) vitamin $B_{12}$
F) vitamin $\mathrm{D}$

Question 12

Which of the following changes occurs during defecation?

A) Internal anal sphincter is relaxed
B) External anal sphincter is contracted
C) Rectal smooth muscle is relaxed
D) Intra-abdominal pressure is lower than when at rest
E) Segmentation contractions predominate

Question 13

Which of the following is characteristic of saliva?

A) Hypotonicity relative to plasma
B) A lower $\mathrm{HCO}_{3}{ }^{-}$ concentration than plasma
C) The presence of proteases
D) Secretion rate that is increased by vagotomy
E) Modification by the salivary ductal cells involves reabsorption of $\mathrm{K}^{+}$ and $\mathrm{HCO}_{3}^{-}$

Question 14

Which of the following substances is secreted in response to an oral glucose load?

A) Secretin
B) Gastrin
C) Cholecystokinin (CCK)
D) Vasoactive intestinal peptide (VIP)
E) Glucose-dependent insulinotropic peptide (GIP)

Question 15

Which of the following is true about the secretion from the exocrine pancreas?

A) It has a higher $\mathrm{Cl}^{-}$ concentration than does plasma
B) It is stimulated by the presence of $\mathrm{HCO}_{3}^{-}$ in the duodenum
C) Pancreatic $\mathrm{HCO}_{3}^{-}$ secretion is increased by gastrin
D) Pancreatic enzyme secretion is increased by cholecystokinin (CCK)
E) It is hypotonic

Question 16

Which of the following substances must be further digested before it can be absorbed by specific carriers in intestinal cells?

A) Fructose
B) Sucrose
C) Alanine
D) Dipeptides
E) Tripeptides

Question 17

Slow waves in small intestinal smooth muscle cells are

A) action potentials
B) phasic contractions
C) tonic contractions
D) oscillating resting membrane potentials
E) oscillating release of cholecystokinin (CCK)

Question 18

A 24-year-old male graduate student participates in a clinical research study on intestinal motility. Peristalsis of the small intestine

A) mixes the food bolus
B) is coordinated by the central nervous system (CNS)
C) involves contraction of circular smooth muscle behind and in front of the food bolus
D) involves contraction of circular smooth muscle behind the food bolus and relaxation of circular smooth muscle in front of the bolus
E) involves relaxation of circular and longitudinal smooth muscle simultaneously throughout the small intestine

Question 19

A 38-year-old male patient with a duodenal ulcer is treated successfully with the drug cimetidine. The basis for cimetidine's inhibition of gastric $\mathrm{H}^{+}$ secretion is that it

A) blocks muscarinic receptors on parietal cells
B) blocks $\mathrm{H}_{2}$ receptors on parietal cells
C) increases intracellular cyclic adenosine monophosphate (CAMP) levels
D) blocks $\mathrm{H}^{+}, \mathrm{K}^{+}$ -adenosine triphosphatase (ATPase)
E) enhances the action of acetylcholine (ACh) on parietal cells

Question 20

When parietal cells are stimulated, they secrete

A) $\mathrm{HCl}$ and intrinsic factor
B) $\mathrm{HCl}$ and pepsinogen
C) $\mathrm{HCl}$ and $\mathrm{HCO}_{3}^{-}$
D) $\mathrm{HCO}_{3}{ }^{-}$ and intrinsic factor
E) mucus and pepsinogen

Question 21

A 44-year-old woman is diagnosed with Zollinger-Ellison syndrome. Which of the following findings is consistent with the diagnosis?

A) Decreased serum gastrin levels
B) Increased serum insulin levels
C) Increased absorption of dietary lipids
D) Decreased parietal cell mass
E) Peptic ulcer disease

Question 22

Which of the following is the site of $\mathrm{Na}^{+}$ -bile acid cotransport?

A) Gastric antrum
B) Gastric fundus
C) Duodenum
D) Ileum
E) Colon