Histology Testbank: Gastrointestinal System 3a

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 lamina propria?
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.
What is another term for the valve of Kerckring?
a. Lacteal
b. Crypts of Lieberkuhn
c. Plicae circulares
d. Striated border
e. Villi

Answer: c

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.

3.
Which type of papillae on the tongue is the smallest?
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.

4.
Where are Peyer's patches located?
a. Esophagus
b. Stomach
c. Small intestine
d. Large intestine
e. Rectum

Answer: c

Peyer's patches are large nodules of lymphatic tissue. They are seen in the
small intestine.

5.
What type of muscle makes up the muscularis externa in the esophagus?
a. Smooth
b. Striated
c. Cardiac
d. both a and b
e. a, b, and c.

Answer: d

The muscularis externa in the upper third of the esophagus is composed of striated muscle and in the lower third it is smooth muscle. The middle third is a blend.

6.
What are mucous surface cells?
a. Simple squamous epithelium
b. Simple cuboidal epithelium
c. Simple columnar epithelium
d. Stratified squamous epithelium
e. Transitional epithelium

Answer: c

The epithelium on the stomach is lined by mucous surface cells which are a simple columnar epithelium.

7.
Which layer consists of only a single layer of epithelial cells and underlying
connective tissue?
a. Mucosa
b. Sub mucosa
c. Muscularis externa
d. Serosa
e. Adventitia

Answer: d

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.

8.
What is another term for the brush border?
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.

9.
Which type of papillae on the tongue is arranged in a "V" shape on the tongue?
a. Filiform papillae
b. Circumvallate papillae
c. Fungiform papillae
d. Foliate papillae
e. All of the above

Answer: b

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.

10.
Which cells secrete intrinsic factor?
a. Parietal cells
b. Oxyntic cells
c. Chief cells
c. 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.