Histology Of Upper GI Tract

Question 1

What is the function of the small intestine?

Answer 1

Digestion via conversion into soluble form for absorption

Question 2

What are the 4 major organs of the digestive tube after the oral cavity?

Answer 2

Esophagus, stomach, small intestine, large intestine

Question 3

Name the layers of each organ from lumen to outside

Answer 3

Mucosa, submucosa, muscularis externa, adventitia/serosa

Question 4

What are the 3 components of the mucosa?

Answer 4

Epithelial lining with mucosal and submucosal glands and ducts
Lamina propria w/vascularized loose CT
Smooth m.

Question 5

What parts of the digestive tract have stratified squamous epithelium?

Answer 5

Oral cavity, oropharynx, esophagus, anal canal

Question 6

What parts of the digestive tract have simple columnar epithelium?

Answer 6

Stomach, small intestine, large intestine, rectum

Question 7

What is the function of the epithelium (for all of the gi tract)?

Answer 7

Selective permeable barrier
Transport, digestion, absorption
Produce hormones

Question 8

What is the lamina propria made of?

What is located there?

What does the lamina propria of the small and large intestines contain?

Answer 8

Vascularized loose CT

MPL - marcophages, plasma cells, lymphocytes

Peyer’s Patch or GALT

Question 9

What is the purpose of the muscularis mucosae of the mucosal layer?

Answer 9

Increase contact area w/food

Propel and mix food in GI tract

Question 10

What is the submucosa made of?

Where are glands present in the submucosa?

Answer 10

Dense irregular CT

Esophagus and duodenum

Question 11

What is the function of the rugae, plicae, and villi?

Answer 11

Increase surface area for absorption

Question 12

What are the 2 layers of muscularis externa?

Answer 12

Circular layer - inner layer around lumen

Longitudinal layer - outer layer along the tube
Contraction reduces the lumen and shortens the tube
Both smooth m.

Question 13

Give the characteristics of the adventitia

Answer 13

Outside the peritoneal cavity
Binds to body wall
Loose CT
Blood vessels and Nerves ONLY

Question 14

Give the characteristics of the serosa:

Answer 14

W/in the peritoneal cavity
Loose CT
Simple squamous epithelium
Blood vessels, nerves, AND FAT

Question 15

What does the lower esophageal sphincter do?

Answer 15

Prevents reflux and regurgitation of stomach contents through contraction
Must relax for food to pass when swallowing

Question 16

Where is the upper esophageal sphincter located?

Answer 16

Near the cricopharyngeus muscle

Question 17

What kind of epithelium is the esophagus?

Answer 17

Non-kertanized stratified squamous

Question 18

What kind of muscle is the upper 1/3 of the esophagus? Fx?

Lower 2/3 muscle? Fx?

Answer 18

Skeletal, voluntary swallowing

Smooth, peristalsis

Question 19

Where does the mucosa transfer from stratified squamous to simple columnar?

Answer 19

At the gastroesophageal junction

Question 20

What does the UES participate in?

Answer 20

Beginning of swallowing

Question 21

what is Barrett’s esophagus?

Due to what?

What does it predispose you to?

Answer 21

Change in esophageal epithelium from stratified squamous to simple columnar
Due to GERD
Adenocarcinoma of the esophagus

Question 22

What is the function of the stomach?

Answer 22

Homogenize and chemically process food

Question 23

What makes up the orad area of the stomach?

Answer 23

Cardia and fundus, LES

Question 24

What makes up the caudad area of the stomach?

Answer 24

Body and antrum

Regulates gastric emptying

Question 25

What are cardiac glands like? What are they lined by?

Answer 25

Simple tubular, coiled at lower end Mucus-secreting cells

Question 26

What are the 5 types of gastric glands?

Answer 26

``` Mucous neck Chief Parietal Stem Gastroenteroendocrine cells ```

Question 27

What are the 2 classes of mucus producing cells?

Answer 27

Surface mucous cells lining the pit | Mucous neck cells located at the opening of the gastric gland into the pit

Question 28

What do mucous cells produce? What is formed? What is trapped?

Answer 28

Mucins and glycoproteins Insoluble gel that forms protective gastric mucosal barrier Bicarbonate ions and neutralizes acidic pH

Question 29

Where do chief cells predominate? Where are they found? What do they make and how?

Answer 29

Lower 1/3 of the gastric gland Pyloric antrum NOT in cardiac glands Pepsinogen and ultimately pepsin via exocytosis

Question 30

What do parietal cells secrete?

Answer 30

HCl and intrinsic factor

Question 31

What causes autoimmune gastritis? | What is the result?

Answer 31

Autoantibodies to H-K dependent ATPase and to intrinsic factor Result is decreased HCl and lack of intrinsic factor leading to B12 deficiency thus producing pernicious anemia

Question 32

What stimulates parietal cells to make HCl? What produces these things?

Answer 32

ACh and Gastrin Enteroendocrine cells

Question 33

What does Helicobacter pylori do? What is the result?

Answer 33

Survives and replicates in the gastric lumen, can live in the pyloric antrum Acid peptic ulcers and adenocarcinoma of the stomach

Question 34

Gastroenteroendocrine cells are members of what? What are the 3 main functions of peptide hormones?

Answer 34

DNES Regulation of water/electrolyte metabolism and enzyme secretion Regulation of gi motility and mucosal growth Stimulation of the release of other peptide hormones

Question 35

What releases secretin? When? Secretin effects? What does secretin stimulate?

Answer 35

Cells in the duodenal glands of Leiberkuhn when gastric contents enter the duodenum Stimulates Brunner's glands bicarbonate to control gastric acid secretion and regulate pH of the duodenum Also stimulates chief cells to secrete pepsinogen, inhibits Gastrin (no HCl is made)

Question 36

What makes Gastrin? Main function? What else can Gastrin activate?

Answer 36

G cells in pyloric antrum Stimulate HCl production via parietal cells CCK to stimulate gallbladder contraction

Question 37

What produces CCK? Function?

Answer 37

Duodenum Stimulate gallbladder, contracts/relaxes sphincter of Oddi when protein and fat-rich chyme enters duodenum

Question 38

Where is GIP produced? What does it stimulate?

Answer 38

Duodenum Insulin release when glucose is in the small intestine

Question 39

How is motilin released and from where? What does it stimulate?

Answer 39

Cyclically every 90 minutes during fasting from upper small intestine, neurally controlled Stimulates gi motility

Question 40

Where is Ghrelin produced? Where does it bind? What does it stimulate?

Answer 40

Stomach (fundus) GH-secreting cells of the anterior hypophysis Stimulates secretion of growth hormone, inc. during fasting

Question 41

What fibers predominate in the lamina propria? | What is rare?

Answer 41

Reticular and collagen fibers Elastic fibers

Question 42

At the level of the distal pyloric antrum, the circular muscle thickens to form what?

Answer 42

Annular pyloric sphincter

Question 43

What increases surface area to facilitate digestion?

Answer 43

Villi