Lecture 7: Histology of Esophagus and Stomach

Question 1

What are the four layers of the GI tract from the lumen to superficial?

Answer 1

1. Mucosa
2. Submucosa
3. Muscularis Externa
4. Serosa/adventitia

Question 2

What are the three layers of the mucosa?

Answer 2

1) Lining epithelium: changes throughout GI tract
2) Lamina propria: lymph and immune cells
3) Muscularis mucosae: controls mucosal glands

Question 3

What composes the submucosal layer?

Answer 3

Dense irregular connective tissue

• neurovasculature
• lymphatics

Question 4

What are the two layers of the muscularis externa?

Answer 4

1. Inner circular layer
2. Outer longitudinal layer

*neurovasculature plexus between layers

Question 5

What is the difference between serosa and adventitia?

Answer 5

Serosa: connective tissue - mesothelial lining covering peritoneal organs
Adventitia: connective tissue - fibrous tissue covering retroperitoneal organs

Question 6

Esophagus: What type of mucosa?

Answer 6

Nonkeratinized stratified squamous

-protective

Question 7

Esophagus: What type of muscle?

Answer 7

Upper third: skeletal
Middle third: skeletal and smooth
Lower third: smooth muscle

Question 8

Esophagus: Is it serosa or adventitia?

Answer 8

Both!
Thoracic esophagus: adventitia
Below diaphragm: serosal

Question 9

What glands are found in the esophagus?

Answer 9

1) Cardiac esophageal glands: produce mucus to protect esophagus from stomach contents
2) Submucosal glands: mucous and serous

Question 10

What are the two sphincters of the esophagus and what do they do?

Answer 10

1) Upper esophageal sphincter: anatomical & swallowing reflex
2) Lower esophageal sphincter: functional and prevents reflux of gastric contents

Question 11

Describe GERD and how the histology changes.

Answer 11

Esophagus marked by chronic inflammation, ulceration

• difficulty in swallowing due to reflux of gastric contents
• mucosal lining of inferior esophagus can change

Question 12

Describe the histology of Barrett’s esophagus.

Answer 12

Columnar mucus-secreting/glandular

Question 13

Describe the histology of the gastroesophageal junction.

Answer 13

Simple columnar

-can see glands and pits

Question 14

What are the four regions of the stomach?

Answer 14

Cardia
Fundus
Body
Pyloric antrum

Question 15

What are the gastric mucosal/longitudinal folds called?

Answer 15

Rugae

-covered by gastric pits

Question 16

Stomach: What type of mucosa?

Answer 16

Simple Columnar Epithelium

-has glands

Question 17

Stomach: What are the three types of muscle found?

Answer 17

1) Circular: forms pyloric sphincter
2) Longitudinal
3) Oblique: helps mix food

Question 18

Stomach: Is it serosa or adventitia?

Answer 18

Serosa

Question 19

What are the three parts of the fundic/gastric gland?

Answer 19

1) Gastric pit
2) Isthmus: where stem cells are found
3) Gastric Gland: where products released

Question 20

What type of cells are found at the neck of the gastric gland?

Answer 20

1) Mucous neck cells
2) Parietal cells: secrete HCl and intrinsic factor
3) Enteroendocrine cells:

Question 21

What type of cells are found at the fundus of the gastric gland?

Answer 21

1) Chief cells: releases pepsinogen and chymosin
2) Enteroendocrine cells
3) Parietal cells

Question 22

What are some hallmarks of the chief cells?

Answer 22

Found in inferior regions of gastric glands:

• abundant Rough ERs
• apical secretory granules

Question 23

What are some hallmarks of the parietal cells?

Answer 23

Found in neck and upper segment of gastric glands:

• large cells
• one or two round nuclei
• cytoplasm intensely eosinophilic

Question 24

Describe the histology of the cardiac glands.

Answer 24

Appear circular and oblique:

• tubular, coiled, branches
• opening with gastric pits

Question 25

Describe the histology of the pyloric glands.

Answer 25

- Branched, coiled, tubular glands between fundus and pylorus - glands empty into pits