Quiz 40: Structure and Function of the Digestive System
Instructor Verified Answers Included
WarofGrades Guaranteed A+ Graded Tutorial
1. In the mouth and stomach, salivary -amylase initiates the digestion of which nutrients?
a. Proteins c. Fats
b. Carbohydrates d. Fiber
2. Which elements in saliva protect against tooth decay?
a. Salivary -amylase and ptyalin
b. Secretin and IgA
c. Endogenous enamelin and salivary -amylase
d. Exogenous fluoride and a pH of 7.4
3. Saliva contains which immunoglobulin (Ig)?
a. IgA c. IgG
b. IgE d. IgM
4. What effect is a result of inhibiting the parasympathetic nervous system with a drug such as atropine?
a. Salivation becomes thinner. c. The pH of saliva changes.
b. Salivation decreases. d. Digestive enzymes are inhibited.
5. Food enters the stomach via which sphincter?
a. Cardiac c. Gastric
b. Upper esophageal d. Fundal
6. Which gastric cells secrete hydrochloric acid and intrinsic factor?
a. Parietal c. G
b. Chief d. H
7. Which cells in the stomach secrete histamine?
a. Oxyntic c. D
b. Chief d. Enterochromaffin-like
8. The presence of chyme in the duodenum stimulates which hormones?
a. Motilin and histamine
b. Secretin and cholecystokinin
c. Enteroglucagon and gastric inhibitory peptide
d. Somatostatin and acetylcholine
9. Which gastric hormone inhibits acid and pepsinogen secretion, as well as decrease the release of gastrin?
a. Bombesin c. Somatostatin
b. Histamine d. Acetylcholine
10. Which enzyme breaks down protein-forming polypeptides in the stomach?
a. Acetylcholine c. Gastrin
b. Pepsin d. Secretin
11. Exposure to which substance protects the mucosal barrier of the stomach?
a. Prostaglandins c. Helicobacter pylori
b. Aspirin d. Regurgitated bile
12. The ileum and jejunum are suspended by folds of the peritoneum that contain an extensive vascular and nervous network. What are these folds called?
a. Ligament of Treitz c. Auerbach folds
b. Mesentery d. Lamina propria
13. Where in the small intestines are lymphocytes, plasma cells, and macrophages produced?
a. Brush border c. Lamina propria
b. Microvilli d. Crypts of Lieberkühn
14. Why are water and electrolytes transported in both directions through tight junctions and intercellular spaces rather than across cell membranes?
a. The intercellular hydrostatic pressure is inadequate to push the water and electrolytes across the cell membranes.
b. A balance of cations and ions among the electrolytes on each side of the cell membranes cannot be maintained.
c. The epithelial cell membranes are formed of lipids that are hydrophobic and therefore repel water.
d. Receptors on those cell membranes are occupied with a diffusion of amino acids and monosaccharides.
15. Which statement best describes the gastrointestinal tract?
a. The gastrointestinal tract is a muscular tube that transports food from the mouth to the stomach.
b. The gastrointestinal tract is a hollow tube that extends from the mouth to the anus.
c. The gastrointestinal tract is a baglike structure that propels partially digested food (chyme).
d. The structure is 5 m long and consists of three segments.
16. Glucose transport enhances the absorption of which electrolyte?
a. Sodium c. Potassium
b. Phosphate d. Chloride
17. What process is capable of increasing both intrathoracic and intraabdominal pressure, thereby facilitating defecation?
a. Relaxation of the internal anal sphincter
b. Intestinal peristalsis
c. Valsalva maneuver
d. Ileogastric reflex
18. Which pancreatic enzyme is responsible for the breakdown of carbohydrates?
a. Trypsin c. Lipase
b. Amylase d. Chymotrypsin
19. The formation of water-soluble molecules to facilitate the absorption of the by-products of lipid hydrolysis is accomplished by:
a. Micelles c. Chylomicrons
b. Phospholipase d. Colipase
20. What is the primary source of physiologic iron?
a. Transferrin from plasma c. Bile from bilirubin
b. Pepsin form pepsinogen d. Heme from animal protein
21. Which statement is incorrect regarding the characteristics of vitamin B12?
a. Vitamin B12 is absorbed in the terminal ileum.
b. Vitamin B12 is absorbed in its free (unbound) form but only in small amounts.
c. Vitamin B12 is necessary for platelet maturation.
d. Vitamin B12 binds to intrinsic factor.
22. Which water-soluble vitamin is absorbed by passive diffusion?
a. Vitamin B6 c. Vitamin K
b. Vitamin B1 d. Folic acid
23. Which vitamin facilitates the absorption of iron by the epithelial cells of the duodenum and jejunum?
a. B6 c. E
b. C d. B12
24. What is the role of the normal intestinal bacterial flora?
a. Metabolizing bile salts, estrogens, and lipids
b. Breaking down proteins into amino acids
c. Facilitating the motility of the colon
d. Metabolizing aldosterone and insulin
25. Kupffer cells are best described as:
a. Natural killer cells that produce interferon-gamma (IFN-)
b. Contractile and therefore capable of regulating the sinusoid blood flow
c. Bactericidal and therefore central to innate immunity
d. Able to metabolize estrogen, progesterone, and androgens
26. Bilirubin is a by-product of the destruction of which aged cells?
a. Platelets c. Leukocytes
b. Protein d. Erythrocytes
27. The process of conjugation of bilirubin in the liver is best described as which transformation?
a. Unconjugated (fat-soluble) bilirubin into urobilinogen
b. Unconjugated (fat-soluble) bilirubin into conjugated (water-soluble) bilirubin
c. Conjugated (water-soluble) bilirubin into unconjugated (fat-soluble) bilirubin
d. Conjugated (water-soluble) bilirubin into urobilinogen
28. Which statement is incorrect regarding gallbladder function?
a. Within 30 minutes of eating, the gallbladder forces bile into the stomach.
b. Cholinergic branches of the vagus nerve mediate gallbladder contraction.
c. Cholecystokinin provides hormonal regulation of gallbladder contraction.
d. The sphincter of Oddi controls the flow of bile from the gallbladder.
29. Which structure synthesizes clotting factors and the vitamin K necessary for hemostasis?
a. Colon c. Gallbladder
b. Spleen d. Liver
30. How many days does it take for the entire epithelial population of the small intestines to be replaced?
a. 30 to 45 c. 7 to 15
b. 15 to 25 d. 4 to 7
31. Which statement is true regarding the state of the intestinal tract at birth?
a. The intestinal tract is colonized by Escherichia coli.
b. The intestinal tract is sterile.
c. Clostridium welchii is present in the intestinal tract but in very small numbers.
d. Streptococcus colonization in the intestinal tract has begun.
32. Gastric emptying is delayed by the presence of which substances? (Select all that apply.)
c. Nonisotonic solutions
33. Which statements are true regarding the ileogastric reflex? (Select all that apply.)
a. The purpose of ileogastric reflex is to inhibit gastric motility.
b. Ileum distension triggers the ileogastric reflex.
c. The ileogastric reflex causes the relaxation of the ileocecal sphincter.
d. Increased gastric secretion triggers the ileogastric reflex.
e. The ileogastric reflex stimulates an increase in ileal motility.
34. Which hormones are involved in the relaxation of the stomach’s fundus during swallowing? (Select all that apply.)
35. Which hormones are involved in regulating gastric motility by making the threshold potential of muscle fibers more negative? (Select all that apply.)
36. What requirements are necessary for calcium to be absorbed through the ileum at concentrations of less than 5 mmol/L? (Select all that apply.)
a. Receptor site on the ileum
b. Vitamin D3
c. Vitamin K
e. A carrier protein
37. Which water-soluble vitamins are dependent on sodium for absorption? (Select all that apply.)
a. Pantothenic acid
b. Vitamin B1
c. Vitamin C
d. Vitamin B12
e. Folic acid
38. Which statement is correct regarding the functions of the pancreas? (Select all that apply.)
a. Cholecystokinin stimulates the release of pancreatic enzymes.
b. Bilirubin and S cells inhibit the secretion of pancreatic enzymes.
c. Pancreatic polypeptide is released after eating.
d. Acetylcholine (ACh) is liberated from the pancreatic branches of the vagus nerve.
e. ACh stimulates the release of pancreatic enzymes.
Match the hormone from the small intestine with its action. Hormones may be used more than once.
______ A. Peptide YY
______ B. Secretin
______ C. Cholecystokinin
______ D. Enteroglucagon
______ E. Pancreatic polypeptide
39. Stimulates the gallbladder to eject bile and the pancreas to secrete alkaline fluid.
40. Stimulates the pancreas to secrete alkaline pancreatic juices.
41. Delays gastric and small bowel emptying.
42. Decreases pancreatic and enzyme secretions.
43. Enhances insulin release, lipolysis, and ketogenesis.