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Flashcards in Lower GI I Deck (47)
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1

Layers of the intestinal wall (from inside to outside)

-Mucosa with lamina propria and muscularis mucosa
- Submucosa
- Muscularis layers
-Serosa

2

Histologic Characteristics of Duodenum

-Villi with wide spatulate or "leaflike" distal shape

- Deep crypts of Lieberkuhn

- Brunner's glands with excretory ducts in submucosa

3

Crypts of Lieberkuhn are _______ ______ glands within the _________

simple tubular glands, intestinal mucosa

4

Crypts of lieberkuhn open between adjacent ______ and extend to ________ _______

villi, muscularis mucosa

5

Cell of the crypts of Lieberkuhn

Goblet cells
Enterocytes
Paneth cells
Enteroendocrine cells

6

Enterocytes are _______ epithelial cells

columnar

7

Characteristics of Enterocytes

-Basal nucleus, perinuclear Golgi, apical brush border

- Produce disaccharidases

- Involved in absorption of proteins, carbohydrates, and lipids

- Enzymes present on apical brush border are important in carbohydrate digestion

- Produce enteropeptidase (enterokinase) which is necessary for the activation of pancreatic zymogens and proenzymes

8

Enterocytes produce

Disaccharidases and enteropeptidase (enterokinase)

9

______ is produced by enterocytes and necessary for the activation of pancreatic zymogens and proenzymes

Enteropeptidase (enterokinase)

10

Characteristics of Paneth cells

-Basal crypt cells
- Prominent eosinophilic granules
- Produce lysozyme to control intestinal flora

11

basal crypt cells with prominent eosinophilic granules

Paneth cells

12

Characteristics of Enteroendocrine cells

-Stain with chromium (chromaffin)
- Agyrophilic (respond to silver stains)
- Produce peptide hormones and serotonin
- May produce pancrine or autocrine secretions
- Analogous to unicellular goblet cells
- formed from endodermal stem cells in all regions of the GI tract

13

Enteroendocrin cells of the crypts of Lieberkuhn produce

peptide hormones and serotonin

14

What are enteroendocrine cells mode of secretion

paracrine or autocrine secretions

15

Brunner glands are found in

submucosa of duodenum

16

Brunner's glands are responsible for

- Formation of bicarbonate and mucus

- Supplements bicarbonate from the pancreas

- Necessary to neutralize gastric acid

17

Histological Characteristics of Jejunum

-Villi longer and more narrow than in Duodenum

- Crypts of Lieberkuhn present

- No glands in submucosa

18

Histologic characteristics of Ileum

-Villi are longer and narrower than in jejunum

-Crypts of Lieberkuhn present

- No glands in submucosa

- Peyer's patches

19

Epithelium of large intestine

- Simple columnar epithelium

- Crypts but no villi

20

Functions of large intestine

-Secretion of mucus for lubrication

- Goblet cell is the prominent cell of the large intestine

- Absorption of fluid

- Formation of fecal mass

- Continuation of digestion initiated in small intestine

21

Location of M cells (antigen-presenting cells)

Ileum

22

The epithelial cells of the GI tract are held together by _______ containing the transmembrane proteins ____ and _____, which function to prevent paracellular transport

occluding junctions, claudins and occludins

23

Characteristics of Paneth Cells

-Basophilic basal cytoplasm

- Supranuclear Golgi complex

- Large, intensely acidophilic apical secretory granules

24

Paneth cells secrete (what are the functions of each secretion)

Lysozyme- increase permeability of bacteria by degrading peptidoglycan goat

- Defensins to increase membrane permeability of target organism

- Tumor necrosis factor- alpha (proinflammatory cytokine)
- may phagocytize some microorganims and help regulate intestinal flora

25

What are the three regions of the small intestine

Duodenum
Jejunum
Ileum

26

______ layer coats intestinal epithelial luminal surface

mucosal

27

The mucosal layer of intestines is secreted by

goblet cells

28

The mucosal layer of intestines is made up of how many layer and what are they

It is made up of 2 layers

- Outer layer contains microorganisms
- Inner layer contains:
- Antimicrobial proteins (from Paneth Cells, Enterocytes, and Goblet cells ) that resist microbial penetration

29

Toll-like receptors are found on the surface of

enterocytes

30

What are toll-like receptors

They are found on the surface of enterocytes
fxn:
- Type of pattern recognition receptor
- Recognize structurally conserved molecules broadly shared by pathogens but distinguish from host molecules (pathogen associated molecular patterns (PAMPs))