Chapter 16 - Digestive System: Oral Cavity and Alimentary Tract

Question 1

The type of epithelium associated with the vermilion zone of the lips is:
(A) stratified squamous nonkeratinized.
(B) pseudostratified ciliated columnar.
(C) stratified squamous keratinized.
(D) stratified cuboidal.
(E) stratified columnar.

Answer 1

C. The external aspect and vermilion zone of the lips are covered by thin skin, which contains a stratified squamous keratinized epithelium. The internal aspect of the lips is lined by a wet mucosa containing a stratified squamous nonkeratinized epithelium (see Chapter 16 II A).

Question 2

Which of the following cell types is present
in the gastric glands of the pyloric stomach?
(A) Goblet cells
(B) Mucous neck cells
(C) Paneth cells
(D) Basal cells
(E) Chief cells

Answer 2

B. Mucous neck cells are located in the neck of gastric glands in all parts of the stomach, whereas only fundic glands contain chief (zymogenic) cells (see Chapter 16 III B 2).

Question 3

Secretin and cholecystokinin are produced and secreted by cells in the lining of the alimentary tract. Which of the following statements about these two substances is true?
(A) They are produced by diffuse neuroendocrine cells (DNES cells) in the lining of the stomach and small intestine.
(B) They are digestive enzymes present within the lumen of the duodenum.
(C) They are produced by Paneth cells.
(D) They are hormones that have target cells in
the pancreas and biliary tract.
(E) They are produced by Brunner glands and released into the lumina of the crypts of Lieberkiihn.

Answer 3

D. Secretin and cholecystokinin are hormones produced by enteroendocrine cells in the small intestine. Secretin stimulates bicarbonate secretion in the pancreas and biliary tract. Cholecystokinin stimulates the release of pancreatic enzymes and contraction of the gall bladder (see Chapter 16 III C 3).

Question 4

If odontoblasts malfunction because of developmental anomalies, which of the following will be affected?
(A) Cementum
(B) Enamel
(C) Dentin
(D) Tooth crown only
(E) Tooth root only

Answer 4

C. Dentin is manufactured by odontoblasts (see Chapter 16 II C 2).

Question 5

Which of the following statements concern­ ing the principal fiber bundles of the periodontal ligament is true?
(A) They are composed of elastin.
(B) They extend from the cementum to the
enamel.
(C) They extend from the dentin to the cementum.
(D) They are composed of collagen.
(E) They extend from one tooth to the next.

Answer 5

D. The principal fiber bundles of the periodontal ligament are composed of collagen fibers. They suspend a tooth in its alveolus, extending from the cribriform plate of the alveolar bone to the cementum on the root of the tooth. The fibers that extend from one tooth to the next are the transseptal fibers of the gingivae (see Chapter 16 II D 1).

Question 6

A patient goes to the emergency depart­ ment, and the physician notes one ofthe clas­ sic symptoms ofappendicitis. Which ofthe following is that symptom?
(A) Apnea
(B) Vomiting of blood
(C) Depressed white cell count
(D) Rectal bleeding
(E) Abdominal pain

Answer 6

E. Rectal bleeding or vomiting of blood often accompanies gastrointestinal pathologies but not appendicitis. Elevated, not depressed, white cell count and abdominal pain are classic signs of appendicitis (see Chapter 16 III D 5 Clinical Considerations).

Question 7

Passage of a bolus through the esophagus into the stomach is facilitated by which of the following?
(A) Peristaltic activity of the esophageal muscularis externa
(B) Peristaltic activity of the gastric muscularis mucosae
(C) Reflux through the pharyngoesophageal sphincter
(D) Smooth muscle in the esophageal muscularis mucosae
(E) Reflux through the gastroesophageal sphincter

Answer 7

A. The smooth muscle of the muscularis mucosae plays no role in the movement of a bolus through the esophagus. This movement is accomplished by peristalsis of the esophageal muscularis externa, which contains both skeletal and smooth muscle. The sphincters at the proximal and distal ends of the esophagus permit movement of food in only one direction, toward the stomach (see Chapter 16 III A 5).

Question 8

The small intestine has three histologically
distinct regions. Which of the following statements concerning the histological differences in the three regions is true?
(A) Peyer patches are present only in the ileum.
(B) Goblet cells are present only in the epithelium of the duodenum.
(C) Brunner glands are located in the
duodenum and jejunum but not
the ileum.
(D) Lacteals are present only in the lamina propria of the ileum.
(E) The muscularis mucosae contains three layers of smooth muscle in the ileum and two layers in the duodenum and jejunum.

Answer 8

A. The primary histological differences in the three regions of the small intestine are the presence of Peyer patches in the lamina propria of the ileum and the presence of Brunner glands
in the submucosa of the duodenum. The duodenum and jejunum lack Peyer patches, and the jejunum and ileum lack Brunner glands. Goblet cells are present throughout the small intestine (see Chapter 16 III C 3).

Question 9

Which of the following materials can be absorbed directly by the surface lining cells of the stomach?
(A) Vitamin B12
(B) Polysaccharides
(C) Chylomicrons
(D) Triglycerides
(E) Alcohol

Answer 9

E. Only a few simple substances, such as alcohol, can be absorbed by the epithelial lining of the stomach (see Chapter 16 III B 1).

Question 10

Which of the following is characteristic of angular cheilitis?
(A) Patients in the early 20s
(B) Presence of herpes virus
(C) Erythematous lesions at the corners of the
mouth
(D) Apnea
(E) High blood levels of secretin

Answer 10

C. The corners of the mouth have painful erythematous lesions (see Chapter 16 II B 2 Clinical Considerations).