Histology of the Small and large intestines Flashcards Preview

GI exam #1 > Histology of the Small and large intestines > Flashcards

Flashcards in Histology of the Small and large intestines Deck (41):
1

What is chyme

semifluid mass from stomach to duodenum

2

What are plicae circulares

they are IN the wall,
includes the mucosa and submucosa
-begin in duodenum and disappear mid ileum

3

What are villi

extensions of mucosa that increase surface area

4

What forms the crypts of Lieberkun?

the villi, they extend deep into the mucosa

5

How can we tell if what we are looking at is a gland or not

if it goes all the way down to the muscularis mucosa, it's a gland

6

What are crypts of Lieberkuhn?

simple tubular glands that increase intestinal surface area
-formed by ivaginations of mucosa between adjacent intestinal cilli

7

What are microvilli?

evaginations of the apical part of the enterocytes to increase surface area
-produce a brush border on the apical border of ENTEROCYTES

8

What are enterocytes?

epithelial cells lining the lumen

9

What is the border between mucosa and submucosa?

muscularis MUCOSA

10

What is muscularis externa responsible for?

segmentation and peristalsis

11

What is the serosa?

a thin layer of loose CT covered by visceral peritoneum (mesothelium)

12

Which layer is the main distribution site of blood and lymphatic flow?

the submucosa

13

What are the 2 capillary plexuses in the small intestine?

villus and pericryptal capillary networks

14

What does the villus capillary plexus supply?

intestinal villus and upper portion of the crypts of lieberkuhn

15

What does the pericryptal capillary plexus supply?

the lower half of the crypts of lieberkuhn

16

What conveys Chyle (lymph-containing lipids) from the intestine to lymph circulate (thoracic duct)?

lacteals
-within a villus

17

What controls the motility of the small intestine?

the ANS through submucosal and myenteric plexi

18

Where does the intrinsic input come from?

the mucosa and muscle wall of the small intestine

19

Where does the extrinsic input come from?

the CNS through parasympathetic nerve trunks (vagus N.)

20

What cell is specific to the duodenum?

brunner's glands
-few goblet cells and leaf like villi

21

Where are the brunner's glands located?

in the submucosa

22

What is a special characteristic of the jejunum?

well developed plicae circulares
-NO brunner's glands or peyer's patches
-more goblet cells

23

What is a special characteristic of the Ileum?

peyer's patches
-LOTS of goblet cells
-finger-like villi

24

What kind of epithelium lines the crypts of lieberkuhn?

simple columnar

25

What are the 4 kinds of cells found int he crypt of lieberkuhn?

1.) absorptive cells, or ENTEROCYTES
2.) goblet cells
3.) paneth cells
4.) enteroendocrine cells
*and stem cells I guess

26

What do the enterocytes have in their membranes?

enzymes! to digest carbs

27

What do goblet cells do?

secrete mucus via exocytosis

28

What do enteroendocrine cells do?

secrete peptide hormones controlling several functions of the GI system

29

What are the 3 things that are secreted from enteroendocrine cells?

Gastrin
Secretin
CCK

30

What does gastrin do?

stimulates gastric motility, HCL (parietal cells), and insulin

31

What does secretin do?

Stimulates pancreatic bicarb secretion and enhances insulin release
-opposite of gastrin except for the insulin part

32

What does CCK do?

acts on pyloric sphincter to slow emptying, stimulates release of bile and pancreatic enzymes

33

What do paneth cells do?

secrete antimicrobial proteins to limit bacteria-enterocyte contact
-enzymatic degradation of bacterial wall or disrupt the bacterial inner membrane

34

What is Crohn's disease

it's when neutrophils get into the crypts of lieberkuhn and destroy the intestinal glands

35

What is the major function of enterocytes in the large intestine?

transport of Ions and Water

36

Where do we stop seeing plicae circulares or villi?

beyond the ileocecal valve
-BUT there's lots of straight tubular glands to lubricate

37

What cellular process removes water and concentrated the chyme into semisolid feces?

active transport of sodium

38

What is the main feature of microvilli of the large intestine?

short

39

What does aldosterone do?

increases the absorption of sodium

40

What does the crypts of lieberkuhn have in the large intestine?

goblet cells, eneteroendocrine, and stem cells
*NO PANETH CELLS* those are in the ileum

41

What smooth muscle layer of the muscularis externa does not aggregate into the taenia coli?

the outer longitudinal smooth muscle layer