GI system II

Question 1

What are the four layers of the GI tube?

Answer 1

1. Mucosa2. Submucosa3. Muscularis externa4. Adventitia or serosa

Question 2

Which GI tube layers have CT associated with them?

Answer 2

1. Serosa2. Adventitia

Question 3

What is the difference between the serosa and adventitia?

Answer 3

Serosa has an additional outer component (mesothelium)

Question 4

What makes up the mucosa?

Answer 4

1. Epithelium on basal lamina2. Lamina propria3. Muscularis mucosae

Question 5

What are the characteristics of the lamina propria?

Answer 5

1. CT, glands, vessels, lymphatic tissue2. Lymphatic vessels with segmental differences

Question 6

What are the characteristics of the muscularis mucosae?

Answer 6

1. Two layers of smooth muscle (inner circular and outer longitudinal)2. Contraction wrinkles mucosa to increase SA

Question 7

What are the characteristics of the submucosa?

Answer 7

1. Dense irregular CT2. Glands are present in esophagus and duodenum3. Meissner’s plexus

Question 8

What are the characteristics of the muscularis externa?

Answer 8

1. Two layers of smooth muscle (inner circular and outer longitudinal)2. Contraction results in peristalsis3. Myenteric (Auerbach’s) plexus

Question 9

What is the submucosal plexus?

Answer 9

1. Parasympathetic postganglionic meurons and sympathetic postganglionic fibers2. Regulates glandular activity, blood flow, muscularis mucosae, and is sensory

Question 10

What is the myenteric plexus?

Answer 10

1. Located in muscularis externa2. Parasympathetic postganglionic neurons and sympathetic postganglionic fibers3. Controls peristalsis

Question 11

What kind of epithelium makes up the mucosa of the esophagus?

Answer 11

Stratified squamous nonkeratinized

Question 12

Where are the cardiac esophageal glands found?

Answer 12

Lamina propria proximally and distally

Question 13

Where are the esophageal glands proper (seromucous) found?

Answer 13

Submucosa

Question 14

What are the characteristics of the muscularis externa in the esophagus?

Answer 14

1. Upper 5% - skeletal2. Upper esophagus - skeletal and smooth3. Lower 50% - smooth

Question 15

How is the adventitia / serosa arranged in the esophagus?

Answer 15

1. Thoracic - adventitia2. Abdominal - serosa

Question 16

What is Barrett’s esophagus?

Answer 16

1. Metaplastic columnar epithelium with goblet cells (PAS / Alcian blue stain highlight goblet cells)2. Demarcation of stratified squamous and simple columnar epithelia3. At risk for progression to adenocarcinoma

Question 17

What is achalasia?

Answer 17

1. Damage to certain neurons in the myenteric plexus causes constriction of the LES2. Distal constricted esophagus demonstrates a characteristic bird’s beak appearance

Question 18

What are the characteristics of the mucosa in the stomach?

Answer 18

1. Simple columnar with mucous cells2. Gastric pits3. Glands empty into gastric pits4. Gland regions isthmus, neck, fundus5. Few lymphatic vessels; in lamina propria around muscularis mucosae

Question 19

What are gastric pits?

Answer 19

Invaginations of surface epithelium into lamina propria

Question 20

What are the characteristics of the fundus and body mucosa?

Answer 20

1. Short gastric pits2. Gastric glands are long with diverse cell population3. Glands divided into isthmus, neck, base

Question 21

What are the cells of the isthmus region of gastric glands?

Answer 21

1. Surface epithelial cells - secrete mucous2. Parietal (oxyntic) cells - secrete HCl and intrinsic factor in response to gastrin 3. Stem cells are located here

Question 22

In which region of the gastric gland are stem cells located?

Answer 22

Isthmus

Question 23

What are the features of the neck region of the gastric gland?

Answer 23

1. Mucous neck cells2. Many parietal cells, some chief cells3. Enteroendocrine cells

Question 24

What are the features of the base region of the gastric gland?

Answer 24

1. Contains many chief cells - pepsinogen is secreted in response to Ach2. Enteroendocrine cells - hormone secreting cells3. Some mucous cells4. Few parietal cells

Question 25

What are the features of the cardiac mucosa of the stomach?

Answer 25

1. Short gastric pits2. Long glands in lamina propria

Question 26

What are the features of the pyloric mucosa of the stomach?

Answer 26

1. Deep gastric pits2. Short glands3. Enteroendocrine cells (G cells secreting gastrin)

Question 27

What are defense mechanisms against ulcers?

Answer 27

1. Mucous and bicarbonate layer2. Cell renewal3. Alkaline tide

Question 28

What is the difference between ulcer and erosion?

Answer 28

1. Erosion - confined to mucosal layer2. Ulcer - penetrates into submucosa

Question 29

What is the gastroduodenal sphincter?

Answer 29

Pyloric sphincter; thickening of muscularis externa, chiefly inner circular layer

Question 30

What are the structures that increase the SA of the small intestine?

Answer 30

1. Plicae circulares - permanent folds of submucosa and mucosa2. Intestinal villi - mucosa3. Microvilli

Question 31

What are the signature features of gluten enteropathy?

Answer 31

1. Enterocytes are disarrayed2. Villus atrophy3. Crypt (intestinal gland) hyperplasia4. Inflammation of lamina propria

Question 32

What are features of Zollinger-Ellison syndrome?

Answer 32

1. Caused by gastrin-secreting tumor2. Tumor may arise in the duodenum, pancreas, or peripancreatic soft tissue

Question 33

What is Passaro’s triangle?

Answer 33

Where 90% of gastrinomas occur:1. Junction of cystic and common hepatic ducts2. Junction of pancreatic head and neck3. Junction of parts 2 and 3 of duodenum