1. Which of these statements about 4 intrinsic factor is true?
a. It is secreted by the stomach.
b. It is a polypeptide.
c. It promotes absorption of vitamin
B12 in the intestine. 5
d. It helps prevent pernicious anemia.
e. All of these are true.
2. Intestinal enzymes such as lactase are a. secreted by the intestine into the chyme.
b. produced by the intestinal crypts (of Lieberkuhn.)
c. produced by the pancreas.
3. Which of these statements about gastric secretion of HCl is false?
b. HCl hydrolyzes peptide bonds.
c. HCl is needed for the conversion of pepsinogen to pepsin.
d. HCl is needed for maximum activity of pepsin.
Most digestion occurs in a. the mouth.
b. the stomach.
c. the small intestine.
d. the large intestine.
Which of these statements about trypsin is true?
a. Trypsin is derived from trypsinogen by the digestive action of pepsin.
b. Active trypsin is secreted into the pancreatic acini.
c. Trypsin is produced in the crypts (of Lieberkuhn).
d. Trypsinogen is converted to trypsin by the brush border enzyme enterokinase.
c. secretin and cholecystokinin from the duodenum.
b. the secretion of an enterogastrone from the duodenum.
c. the lowering of gastric pH.
8. The first organ to receive the blood-borne products of digestion is a. the liver.
b. the pancreas.
9. Which of these statements about hepatic portal blood is true?
a. It contains absorbed fat.
b. It contains ingested proteins.
c. It is mixed with bile in the liver.
d. It is mixed with blood from the hepatic artery in the liver.
10. Absorption of salt and water is the principal function of which region of the GI tract?
a. esophagus b. stomach
b. release of pancreatic enzymes.
c. contraction of the gallbladder.
12. Which of these statements about vitamin B12 is false?
a. Lack of this vitamin can produce pernicious anemia.
b. Intrinsic factor is needed for absorption of vitamin Bj2.
c. Damage to the gastric mucosa may lead to a deficiency in vitamin B12.
d. Vitamin B12 is absorbed primarily in the jejunum.
13. Which of these statements about starch digestion is false?
a. It begins in the mouth.
b. It occurs in the stomach.
c. It requires the action of pancreatic amylase.
d. It requires brush border enzymes for completion.
c. Triglycerides are resynthesized from monoglycerides and fatty acids in the intestinal epithelial cells.
15. Which of these statements about contraction of intestinal smooth muscle is true?
a. It occurs automatically.
b. It is increased by parasympathetic nerve stimulation.
c. It produces segmentation.
d. All of these are true.
Test Your Understanding of Concepts and
1. Explain how the gastric secretion of HCl and pepsin is regulated during the cephalic, gastric, and intestinal phases.1
2. Describe how pancreatic enzymes become activated in the lumen of the intestine. Why are these mechanisms needed?
4. Describe the mechanisms that are believed to protect the gastric mucosa from self-digestion. What factors might be responsible for the development of a peptic ulcer in the stomach?
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