GI system II Flashcards

1
Q

What are the four layers of the GI tube?

A
  1. Mucosa2. Submucosa3. Muscularis externa4. Adventitia or serosa
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2
Q

Which GI tube layers have CT associated with them?

A
  1. Serosa2. Adventitia
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3
Q

What is the difference between the serosa and adventitia?

A

Serosa has an additional outer component (mesothelium)

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4
Q

What makes up the mucosa?

A
  1. Epithelium on basal lamina2. Lamina propria3. Muscularis mucosae
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5
Q

What are the characteristics of the lamina propria?

A
  1. CT, glands, vessels, lymphatic tissue2. Lymphatic vessels with segmental differences
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6
Q

What are the characteristics of the muscularis mucosae?

A
  1. Two layers of smooth muscle (inner circular and outer longitudinal)2. Contraction wrinkles mucosa to increase SA
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7
Q

What are the characteristics of the submucosa?

A
  1. Dense irregular CT2. Glands are present in esophagus and duodenum3. Meissner’s plexus
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8
Q

What are the characteristics of the muscularis externa?

A
  1. Two layers of smooth muscle (inner circular and outer longitudinal)2. Contraction results in peristalsis3. Myenteric (Auerbach’s) plexus
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9
Q

What is the submucosal plexus?

A
  1. Parasympathetic postganglionic meurons and sympathetic postganglionic fibers2. Regulates glandular activity, blood flow, muscularis mucosae, and is sensory
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10
Q

What is the myenteric plexus?

A
  1. Located in muscularis externa2. Parasympathetic postganglionic neurons and sympathetic postganglionic fibers3. Controls peristalsis
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11
Q

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

A

Stratified squamous nonkeratinized

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12
Q

Where are the cardiac esophageal glands found?

A

Lamina propria proximally and distally

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13
Q

Where are the esophageal glands proper (seromucous) found?

A

Submucosa

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14
Q

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

A
  1. Upper 5% - skeletal2. Upper esophagus - skeletal and smooth3. Lower 50% - smooth
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15
Q

How is the adventitia / serosa arranged in the esophagus?

A
  1. Thoracic - adventitia2. Abdominal - serosa
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16
Q

What is Barrett’s esophagus?

A
  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
17
Q

What is achalasia?

A
  1. Damage to certain neurons in the myenteric plexus causes constriction of the LES2. Distal constricted esophagus demonstrates a characteristic bird’s beak appearance
18
Q

What are the characteristics of the mucosa in the stomach?

A
  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
19
Q

What are gastric pits?

A

Invaginations of surface epithelium into lamina propria

20
Q

What are the characteristics of the fundus and body mucosa?

A
  1. Short gastric pits2. Gastric glands are long with diverse cell population3. Glands divided into isthmus, neck, base
21
Q

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

A
  1. Surface epithelial cells - secrete mucous2. Parietal (oxyntic) cells - secrete HCl and intrinsic factor in response to gastrin 3. Stem cells are located here
22
Q

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

A

Isthmus

23
Q

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

A
  1. Mucous neck cells2. Many parietal cells, some chief cells3. Enteroendocrine cells
24
Q

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

A
  1. Contains many chief cells - pepsinogen is secreted in response to Ach2. Enteroendocrine cells - hormone secreting cells3. Some mucous cells4. Few parietal cells
25
Q

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

A
  1. Short gastric pits2. Long glands in lamina propria
26
Q

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

A
  1. Deep gastric pits2. Short glands3. Enteroendocrine cells (G cells secreting gastrin)
27
Q

What are defense mechanisms against ulcers?

A
  1. Mucous and bicarbonate layer2. Cell renewal3. Alkaline tide
28
Q

What is the difference between ulcer and erosion?

A
  1. Erosion - confined to mucosal layer2. Ulcer - penetrates into submucosa
29
Q

What is the gastroduodenal sphincter?

A

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

30
Q

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

A
  1. Plicae circulares - permanent folds of submucosa and mucosa2. Intestinal villi - mucosa3. Microvilli
31
Q

What are the signature features of gluten enteropathy?

A
  1. Enterocytes are disarrayed2. Villus atrophy3. Crypt (intestinal gland) hyperplasia4. Inflammation of lamina propria
32
Q

What are features of Zollinger-Ellison syndrome?

A
  1. Caused by gastrin-secreting tumor2. Tumor may arise in the duodenum, pancreas, or peripancreatic soft tissue
33
Q

What is Passaro’s triangle?

A

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