Histology: GI Tract

Question 1

What are the 4 histologic layers of the GI tract?

Answer 1

Mucosa; submucosa; muscularis externa, and adventitia/serosa

Question 2

What are the components of the submucosal layer?

Answer 2

• Connective Tissue
• Vessels
• Meissner Plexus

Question 3

What is the location of the Meissner Plexus?

Answer 3

Submucosa

Question 4

What is the location of the Auerbach Plexus?

Answer 4

In between the inner and outer muscle layers in the muscularis externa

Question 5

What epithelium covers the esophagus?

Answer 5

Nonkeratinized stratified squamous epithelium

Question 6

What epithelium covers the stomach?

Answer 6

Columnar epithelium

Question 7

What epithelium covers the small intestine?

Answer 7

Villi and microvilli

Question 8

What epithelium covers the appendix?

Answer 8

Columnar epithelium

Question 9

What epithelium covers the large intestine?

Answer 9

Columnar epithelium with no paneth cells but a lot of goblet cells

Question 10

What epithelium covers the anal canal?

Answer 10

Stratified Squamous Epithelium

Question 11

What are the 4 parts of the stomach?

Answer 11

• Cardia
• Fundus
• Body
• Pylorus

Question 12

What do parietal cells secrete?

Answer 12

HCl and Intrinsic Factor

Question 13

What do chief cells secrete?

Answer 13

Pepsinogen

Question 14

Crypts of Lieberkuhn

Answer 14

The epithelia of the villi extend down into the lamina propria where they form crypts. Many important cells reside in the crypts, including those involed in host defense and signaling.

Question 15

Taenia Coli

Answer 15

Three narrow bands of longitudinal muscle

Question 16

Contrast vili vs plicae circulares.

Answer 16

Plicae circulars are are large valvular flaps projecting into the lumen of the small intestine that are covered with villi.

Question 17

What cells make up the epithelium of the inside of the mouth and surface of the tongue?

Answer 17

Nonkeratinized stratified squamous epithelium

Question 18

What is beneath the submucosa?

Answer 18

Muscularis externa

Question 19

When is the outermost layer of tissue called serosa?

Answer 19

Call serosa if covered my mesothelium; adventitia otherwise

Question 20

What is unique about the muscularis externa in the esophagus?

Answer 20

It has some skeletal muscle fibers

Question 21

Cardia

Answer 21

1st part that is separated from the esophagus by the cardiac sphincter

Question 22

Fundus and Body

Answer 22

Largest part of the stomach and the glands have parietal and chief cells

Question 23

Pylorus

Answer 23

Glands are mainly mucus secreting with there being 2 specialized cells: G cells and D cells

Question 24

What do D cells secrete?

Answer 24

Somatostatin

Question 25

What do G cells secrete?

Answer 25

Gastrin

Question 26

What color are the parietal cells?

Answer 26

Pink

Question 27

What color are the chief cells?

Answer 27

Blue

Question 28

What is the feature of the duodenum?

Answer 28

Brunner Glands

Question 29

What is the feature of the jejunum?

Answer 29

Long villi and increased goblet cells – no Brunner glands or Peyer patches

Question 30

What is the feature of the ileum?

Answer 30

Short villi, many goblet cells, and lymphatic nodules in the submucosa called Peyer patches