Histology Testbank: Gastrointestinal System 4a

Instructions: For each histology question, pick the one best answer. This histology test bank is also useful for the histology questions on the USMLE (USMLE step 1).

1.
Which layer contains the lining epithelium?
a. Mucosa
b. Sub mucosa
c. Muscularis externa
d. Serosa
e. Adventitia

Answer: a

The mucosa is the innermost layer of the GI tract. It consists of epithelium, lamina propria, and muscularis mucosa.

The submucosa is connective tissue. Within it are lymphatic vessels and nerve plexuses. Meissner's plexus is located in the submucosa.

The muscularis externa consists of thick layers of smooth muscle. It contains Auerbach's plexus.

The outer layer of the GI tract is either an adventitia or serosa. The serosa consists of only a single layer of epithelial cells and underlying connective tissue. The adventitia is the outer layer of the GI tract when it is abutting another organ the posterior abdominal wall.

2.
Which type of papillae on the tongue does NOT contain taste buds?
a. Filiform papillae
b. Circumvallate papillae
c. Fungiform papillae
d. Foliate papillae
e. All of the above

Answer: a

The papillae on the tongue are located anteriorly to the sulcus terminalis. The tongue contains primarily three types of papillae: filiform papillae, circumvallate papillae and fungiform papillae. The filiform papillae are the smallest and most abundant. Filiform papillae are the only papillae on the tongue which do not contain taste buds. Circumvallate papillae large papillae arranged in a "V" shape. Fungiform papillae are mushroom shaped. Foliate papillae are not well developed in man and are seen on the edges of the tongue. Taste buds are found on cicumvallate, fungiform, and foliate papillae.

3.
Which layer contains Auerbach's plexus?
a. Mucosa
b. Sub mucosa
c. Muscularis externa
d. Serosa
e. Adventitia

Answer: c

The mucosa is the innermost layer of the GI tract. It consists of epithelium, lamina propria, and muscularis mucosa.

The submucosa is connective tissue. Within it are lymphatic vessels and nerve plexuses. Meissner's plexus is located in the submucosa.

The muscularis externa consists of thick layers of smooth muscle. It contains Auerbach's plexus.

The outer layer of the GI tract is either an adventitia or serosa. The serosa consists of only a single layer of epithelial cells and underlying connective tissue. The adventitia is the outer layer of the GI tract when it is abutting another organ the posterior abdominal wall.

4.
Which cells secrete hydrochloric acid?
a. Parietal cells
b. Oxyntic cells
c. Chief cells
d. Mucous neck cells
e. Both a and b

Answer: e

Chief cells secrete pepsinogen. Pepsinogen is the precursor for pepsin. Parietal cells are also called oxyntic cells. They secrete hydrochloric acid and intrinsic factor. Mucous neck cells contain mucinogen granules.

5.
What is another term for the intestinal glands?
a. Lacteal
b. Crypts of Lieberkuhn
c. Plicae circulares
d. Striated border
e. Villi

Answer: b

There are several features of the small intestine.

The lymphatic capillary within a villus of the small intestine is a lacteal.

Crypts of Lieberkuhn are the intestinal glands.

The plica circulares is a projection with a core of submucosa. The plica circulares is also called the valve of Kerckring.

Microvilli that are seen on the epithelial cells in the small intestine form the brush border or striated border.

Villi are finger like projections of mucosa seen in the small intestine.

6.
Which organ has a mucosa lined by nonkeratinized stratified squamous epithelium?
a. Esophagus
b. Stomach
c. Small intestine
d. Large intestine
e. Rectum

The mucosa of the esophagus is mucosa lined by nonkeratinized stratified squamous epithelium.

7.
What are the folds of the stomach called?
a. Ruffled border
b. Taeniae coli
c. Gastric glands
d. Rugae
e. Gastric pits

The folds of the empty stomach are called rugae.

8.
Which type of papillae on the tongue is mushroom shaped?
a. Filiform papillae
b. Circumvallate papillae
c. Fungiform papillae
d. Foliate papillae
e. All of the above

Answer: c

The papillae on the tongue are located anteriorly to the sulcus terminalis. The tongue contains primarily three types of papillae: filiform papillae, circumvallate papillae and fungiform papillae. The filiform papillae are the smallest and most abundant. Filiform papillae are the only papillae on the tongue which do not contain taste buds. Circumvallate papillae large papillae arranged in a "V" shape. Fungiform papillae are mushroom shaped. Foliate papillae are not well developed in man and are seen on the edges of the tongue. Taste buds are found on cicumvallate, fungiform, and foliate papillae.

9.
Which layer contains the muscularis mucosa?
a. Mucosa
b. Sub mucosa
c. Muscularis externa
d. Serosa
e. Adventitia

Answer: a

The mucosa is the innermost layer of the GI tract. It consists of epithelium, lamina propria, and muscularis mucosa.

The submucosa is connective tissue. Within it are lymphatic vessels and nerve plexuses. Meissner's plexus is located in the submucosa.

The muscularis externa consists of thick layers of smooth muscle. It contains Auerbach's plexus.

The outer layer of the GI tract is either an adventitia or serosa. The serosa consists of only a single layer of epithelial cells and underlying connective tissue. The adventitia is the outer layer of the GI tract when it is abutting another organ the posterior abdominal wall.

10.
What are microvilli called that are seen in the small intestine?
a. Lacteal
b. Crypts of Lieberkuhn
c. Plicae circulares
d. Striated border
e. Villi

Answer: d

There are several features of the small intestine.

The lymphatic capillary within a villus of the small intestine is a lacteal.

Crypts of Lieberkuhn are the intestinal glands.

The plica circulares is a projection with a core of submucosa. The plica circulares is also called the valve of Kerckring.

Microvilli that are seen on the epithelial cells in the small intestine form the brush border or striated border.

Villi are finger like projections of mucosa seen in the small intestine.