Histology of the upper GI tract: Esophagus and stomach Flashcards Preview

GI exam #1 > Histology of the upper GI tract: Esophagus and stomach > Flashcards

Flashcards in Histology of the upper GI tract: Esophagus and stomach Deck (27):
1

What is the outer layer of the esophagus called?

adventitia
-it's serosa for the rest of the GI tract

2

What is lamina propria?

vascularized loose CT under the epithelial layer
-lymphatic nodules and scattered immunocompitent cells

3

In what layer are glands present in the esophagus and the duodenum?

the submucosa

4

What are rugae (stomach) or Plicae (small intestine)?

folds that include both mucosa and submucosa

5

What extends alone into the lumen as villi?

mucosa

6

What does contraction of the circular muscle layer do?

reduces the lumen

7

What does contraction of the longitudinal muscle layer do?

shortens the tube

8

What is the difference between adventitia and serosa?

-adventitia is outside the peritoneal cavity while the serosa is IN the peritoneal cavity
-serosa seems to have more stuff in it

9

What does the lower esophageal sphincter do?

helps prevent reflux through contraction
-must relax to let the food through

10

What is the muscle like going down the esophagus?

goes from skeletal to smooth

11

What is the main difference between the esophagus and the stomach epithelium

Esoph has stratified squamous
-stomach has simple columnar

12

What is Barret's esohpagus?

when abnormal columnar epithelium replaces the stratified squamous in the esophagus
-result of chronic GERD and predisposed to adenocarcinoma

13

What kinds of cells are in the gastric glands?

mucous neck cells
chief cells
parietal cells
stem cells
gastroenteroendocrine cells

14

What do mucous cells do?

2 classes
-both produce mucins which are glycoproteins
-make the protective mucus blanket which traps bicarb

15

What do chief cells do?

rapidly exocytose the pepsinogen in response to feeding
-not present in cardiac glands or pyloric antrum

16

What do parietal cells do?

make HCl and intrinsic factor
-they also have CA and the H+/K+ ATPase on the microvilli

17

What causes autoimmune gastritis?

autoantibodies to the ATPase and intrinsic factor
-results in lower acid in gastric juice and lower intrinsic factor

18

What is a secondary effect of autoimmune gastritis?

B12 deficiency which disrupts the formation of RBC's int he bone marrow, leading to pernicious anemia

19

What stimulates parietal cells to secret HCl?

Parasympathetic Ach and the peptide gastrin made by the enteroendocrine cells of the pyloric antrum
*Ach also stimulates the release of gastrin

20

What was the bacteria that can live in the hostlie environment of the stomach?

Helicobacter pylori
-no clinical symptoms... can lead to peptic ulcers and adenocarcinoma

21

What are the functions of the gastroenteroendocrine cells?

-to make gastrin
-regulate water and electrolyte metabolism and enzyme secretion
-regulate GI motility and mucosal growth
-stimulation of the release of other peptide hormones

22

What is secretin?

-released by cells in the duodenal glands of lieberkuhn
-stimulates pancreatic and duodenal bicarb and fluid release to control the gastric acid secretion and regulates the pH of the exocrine pancreas
-also stimulates chief cells to secrete pepsinogen and inhibits gastrin release to reduce HCl secretion in the stomach

23

What does gastrin do?

stimulates production of HCl by parietal cells
-Gastrin is made by G cells in pyloric antrum

24

What does CCK do?

produced by duodenum
-stimulate gall bladder contraction and relaxation of the sphincter of Oddi when protein and fat-rich chyme enters the duodenum

25

What doe GIP do?

stimulates insulin release when GLc is detected in the SI
-also made by the duodenum

26

What does Motilin do?

It is just released cyclically when fasting, neural control mechanism regulates it

27

What does Ghrelin do?

made in the fundus of the stomach
-binds receptors in Growth hormone-secreting cells
-stimulates secretion of growth hormone
-levels increase during fasting triggering hunger by acting on the hypothalamic feeding centers