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Flashcards in Lower GI Tract Deck (61)
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1

What is the small intestine the principal site for?

For absorption of digestion products by cells of the epithelial lining

2

What three regions make up the small intestine

the duodenum, the jejunum and the ileum

3

How long is the small intestine in adults

4-6metres

4

The mucosa and the submucosa of the small intestine is of what shape?

Highly folded

5

What is the plicae circularis (folds of Kerckring)?

They are large deep permanent folds of the mucosa and sub mucosa

6

What are the villi

finger like projections

7

where are the microvilli found in the small intestine?

On the enterocytes

8

What is an enterocyte?

Enterocytes, or intestinal absorptive cells, are simple columnar epithelial cells found in the small intestine.

9

What is the lamina propria?

rich vascular and lymphatic network to absorb products of digestion

10

What is the prominent feature of the small intestine found in the lamina propria called?

Peyer's patches

11

What are peyers patches?

Small masses of lymphatic tissue

12

Where are peyers patches found least and most in the small intestine?

Least in duodenum and most prominent in terminal ileum

13

How would you describe the shape of the peyers patches?

Groups of lymphoid nodules which bulge dome like into the lumen

14

What is the function of the peyers patches?

Function as an immune surveillance system

15

What cells make up the peyers patches?

Germinal centre of proliferating and maturing b cells surrounded by a mantle of small resting lymphocytes

16

What is the epithelium overlying the domes of the peyers patches specialised for?

Antigen uptake

17

What is the germinal centre of the peyers patches made of cell wise?

b cells

18

what is the mantle of the peyers patches made of cell wise?

resting lymphocytes

19

What type of epithelium cell are villi lined by?

simple columnar epithelium

20

The epithelium cells between villi of the small intestine invaginate to form what structure?

The crypts of Lieberkuhn

21

What types of cells are present in the crypts? list six

Enterocytes, goblet cells, paneth cells, neuroendocrine cells, stem cells and intraepithelial lymphocyte

22

what are enterocytes?

most numerous, tall columnar and have surface microvilli

23

What do goblet cells present in the crypts produce?

mucin

24

what are paneth cells

form base of crypts, eosinophilic apical granules. release lysozyme, phospholipase a2, defensins

25

what are neuroendocrine cells

produce locally acting hormones,

26

what are stem cells

differentiate into the other five types of cells mentioned

27

what is the function of intraepithelial lymphocytes

immune defence

28

list three locally acting hormones the endocrine cells may secrete in the small intestine

somatostatin, secretin and serotonin

29

What is the duodenum?

the first part of the small intestine

30

where is the duodenum attached to the stomach?

To the pylorus