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Flashcards in Intestines Deck (20)
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1

General Plan of GI tract

-Mucosae (epithelium,
lamina propria, muscularis mucosae
-Submucosae
-Muscularis Externa
-Adventitia (CT) or Serosa (CT and epithelium)

2

Structures responsible for the increased surface of the small intestine

plicae circulares (folds of submucosa)
Villi (folds of mucosa)
Crypts of Lieberkuhn (Glands)
Microvilli with glycocalyx

3

A jejunum with celiac's disease will have

more connective tissue with lymphocytes

4

Duodenum characteristics

-Brunner’s gland
(in submucosa)
-Distal part: numerous plicae circulares

5

Jejunum char

-Numerous plicae circulares
-Numerous villi
-no glands in submucosa
-no Payer’s patches

6

Ileum char

Peyer’s patches (M cells)
Middle part: reduced number and size of plicae circulares

7

Mucosa of the small intestine

villi – mucosal projections containing lacteal
crypts of Lieberkühn – intestinal glands in the mucosa
epithelium: simple columnar (covers villi and crypts)
Gut Associated Lymphatic Tissue (GALT) in the lamina propria
Mucosa and submucosa
-plicae circulares

8

Small Intestine: Epithelium- Cell types

absorptive cells
goblet cells
Paneth cells
enteroendocrine cells
M cells (microfold cells)
stem cells – regenerative cells

9

absorptive cells

with microvilli –brush/striated border with glycocalyx, contain enzymes

10

goblet cells

unicellular mucin-secreting glands (high number in the ileum)

11

Paneth cells

(in the crypts), secretion: antibacterial lysozyme. Paneth cells play a role in regulation of normal bacterial flora of the small intestine (absent in large intestine).

12

enteroendocrine cells

hormones secretion: gastrin, cholecystokinin (CCK), secretin, gastric inhibitory peptide (GIP), somatostatin, vasoactive intestinal polypeptide (VIP), motilin, enteroglucagon

13

M cells (microfold cells)

cover enlarged lymphatic nodules, e.g., Peyer’s patch, transport antigens.

14

Large intestine summary

no villi, no folds
many glands – crypts of Lieberküh
lamina propria: thick layer of collagen, GALT present (M cells), no lacteal
- Submucosa
-no plicae curculares
  - Muscularis externa
-inner circular layer (thin)
-outer longitudinal layer has three bands (teniae coli)

15

Large Intestine: cell types

Epithelium: simple columnar
A large number of commensal bacteria are found in the large intestine and oral cavity.
Absorptive cells with microvilli and glycocalyx (no digestive enzymes)
Goblet cells (higher number in the lower colon)
Enteroendocrine cells
Stem cells (regenerative cells)
No Paneth Cells

16

Large Intestine: Ulcerative Colitis

Mucosa is lost over extensive area, with ulceration and destruction of the absorptive epithelium. results in diharrea

17

Appendix summary

- Epithelium: absorptive cells and M cells, few goblet cells.
- Lymphatic nodules: in mucosa and submucosa
- Muscularis externa: thick inner circular layer and outer longitudinal layer, no teniae coli 

18

Anal Canal epithelium

Stratified squamous
epithelium

19

Colon, Rectum epithelium

simple columnar
epithelium

20

anal skin

keratinizing stratified squamous