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Digestive tract

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Digestive tract Comparative of different part of digestive tract Appendix Fewer and shorter intestinal glands and more lymph tissue Gastrointestinal ... – PowerPoint PPT presentation

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Title: Digestive tract


1
Digestive tract
2
  • ---Digestive system
  • Digestive tract
  • Digestive gland

3
  • 1. Components of digestive tract
  • ---oral cavity
  • ---pharynx
  • ---esophagus
  • ---stomach
  • ---small intestine
  • ---large intestine

4
  • 2. General structure of digestive tract
  • mucosa, submucosa, muscularis externa, adventitia

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  • 1) mucosa
  • ---epithelium
  • stratified squamous epi.
  • simple columnar epi
  • ---lamina propria LCT-compact CT contain more
    cells and fiber
  • BV, LV-capillaries
  • Lymphoid T
  • glands structures formed by invagination of epi.
    into lamina propria
  • ---muscularis mucosa a thin layer of SM

7
  • 2) submucosa more dense CT
  • small artery and vein, LV
  • glands (esophagus and duodenum)
  • submucosa N plexus
  • -multipolar N
  • -unmyelinated NF
  • -function regulate the contract of SM
    and secreting of gland
  • Plica projection of mucosa and submucosa

8
mucosasubmucos
Plica
9
  • 3) muscularis externa
  • smooth muscle
  • skeletal muscle
  • inner circular and outer longitudinal
  • Nerve plexus regulate the movement of M
  • 4) adventitia CT
  • serosa CT mesothelium
  • fibrosa LCT

10
Nerve plexus between layers of muscularis
  • ?cell body of nerve cells

11
serosa
fibrosa
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3. Esophagus
  • 1)      mucosa
  • epithelium stratified squamous epi.
  • lamina propria compact CT
  • muscularis mucosa longitudinal arranged SM
  • 2)      submucosa
  • LCT
  • esophageal gland mucous gland

14
  • 3)      muscularis
  • inner circular and outer longitudinal
  • upper 1/3 skeletal muscle
  • middle 1/3 mixed of skeletal M and smooth muscle
  • lower 1/3 smooth muscle
  • 4) adventitia fibrosa

15
HE Slidemucosasubmucos
Cross section
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Barrett Esophagus is a chronic complication of
gastroesophageal re?ux disease (GERD),
characterized by metaplasia of the strati?ed
squamous epithelium of the lower esophagus into a
specialized glandular epithelium with goblet
cells. And the in?ammatory cells (mainly
lymphocytes and plasma cells) are in?ltrating the
connective tissue.
18
Esophageal Carcinoma is a malignant neoplasm that
stems from the epithelial cells lining the inner
surface of the esophagus. Worldwide, squamous
cell carcinoma is the most common type of
esophageal. Pathological changes include
ulcerations, exophytic masses, and thickening and
narrowing of the lumen. This photomicrograph
shows a moderately differentiated squamous cell
carcinoma with focal keratin production in the
center, called a keratin pearl.
19
4. Stomach
  • ---dilated part
  • ---store food temporarily
  • ---digest protein primarily
  • ---absorb part of water and ions

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General structure
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Stomach
Mucosa ---plica-longitudinal ---shallow ditch-
gastric area(2-6mm) ---gastric pit- small
depressions
26
Stomach
  • ?epithelium simple columnar epi
  • surface mucous cell
  • -tall columnar
  • -N ovoid, basally-located
  • -mucinogen granule
  • -tight junction
  • -high HCO3- undissolved mucus

27
Stomach
  • ?lamina propria CT contains fibroblast, LC,
    plasma cell, mast cell and eosinophil, SM
  • gastric gland(fundic gland)-oxyntic gland
  • cardiac gland mucous gland
  • pyloric gland mucous gland

28
parietal cell ---LM large, pyramidal or
spherical/round centrally-located
nucleus/eosinophilic cytoplasm
29
  • EM
  • intracellular secretory canaliculus-invagination
    s
  • tubulovesicular system
  • mitochondria

30
  • ---function
  • i. secret hydrochloric acid (HCl)
  • -synthesis processes of HCl in intracellular
    secretory canaliculus
  • H K -ATP pump get H from cell
  • Cl- channel get Cl- from blood
  • H Cl-?HCl (intracellular secretort canaliculi)
  • -function of HCl
  • HCl
  • ?
  • pepsinogen?pepsin
  • kill the bacterium

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  • ii.  secret intrinsic factor- glycoprotein
    VB12?absorption of VB12

33
  • a. chief cell or zymogenic cell
  • ---structure
  • LM
  • columnar
  • Round, basally-located Nucleus
  • cytoplasm
  • /basal-basophilic
  • /apical-zymogen granules
  • EM RER, Golgi apparatus
  • ---function secret pepsinogen

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  • c. mucous neck cell
  • less, neck part
  • columnar
  • flattened, basally-located N
  • pale stain in HE stain
  • d. stem cell undifferentiated cell
  • e. endocrine cell
  • ECL cell secreting histamine, promote secretion
    of parietal cell
  • D cell secreting somatostatin, inhibit the
    secretion of parietal cell

36
  • 1.chief cell
  • 2.parietal cell
  • 3.mucous neck cell

37
  • ? Muscularis mucosa inner circular and outer
    longitudinal arranged SM
  • 2)  submucosa CT with BV, LV, N and fat cell
  • 3)    muscularis thicker
  • inner oblique
  • middle circular
  • outer longitudinal
  • 4) advantitia serosa

38
Gastric Ulcer (Peptic Ulcer) are chronic mucosal
lesions that occur in the gastro-intestinal
tract. Morphologically, peptic ulcers are usually
small, round to oval in shape, less than 4 cm in
diameter with well de?ned margins without
elevation, and have a clean, smooth base. This
image shows the transition from gastric mucosa to
ulcer, showing a ?brinopurulent surface with
underlying granulation tissue. The gastric mucosa
shows chronic gastritis with plasma cells within
the lamina propria and intestinal metaplasia
(note the goblet cells).
39
5. Small intestine
  • ---duodenum
  • ---jejunum
  • ---ileum

40
SEM for villus
41
Plica Villus
Microvillius Cell coat
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  • 1)      Mucosa
  • ---circular plica
  • ---intestinal villus
  • ---small intestinal gland

45
  • ?epithelium
  • ---absorptive cell
  • microvilli striated-border
  • -1-1.4um long, 80nm in D, 2000-3000
  • -enlarge the surface area to 30 times
  • cell coat
  • -0.1-0.5um
  • -enzymes trypsinogen, amylase - glucose and
    protein
  • enzymes-adipose
  • SER

46
  • ---goblet cell

47
  • ?lamina propria CT (LC, macrophage, plasma cell
    and eosinophil and mast cell)
  • a. villus is the projection of epithelium and
    lamina propria
  • epithelium absorptive cell, goblet cell and
    endocrine cell
  • lamina propria CT with central lacteal,
    fenestrated cap. and SM

48
Striated border central lacteal
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  • b. small intestinal gland is the
    invagination of epi.into propria
  • absorptive cell
  • goblet cell
  • endocrine cell
  • stem cell
  • Peneth cell

52
  • Peneth cell
  • LM
  • -pyramidal, basally- located, in groups
  • -apical acidophilic G- contain
    defensin(cryptdin), Lysozyme
  • EM
  • -protein-secreting cell feature
  • Function related to immune function

53
Peneth cell
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  • ?muscularis mucosa SM inner circular and outer
    longitudinal
  • 2)      submucosa CT
  • Large BV and LV
  • duodenal gland mucous gland-secreting epidermal
    growth factor, promote the epithelial cell
    proliferation of small intestine

58
  • 3)  muscularis SM, inner circular and outer
    longitudinal
  • 4)   adventitia serosa and less fibrosa

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61
Peptic Duodenitis is an in?ammatory process
caused by chronic exposure of the duodenal mucosa
to increased levels of gastric acid and is
usually found in the ?rst portion of the
duodenum, the duodenal bulb.. This
photomicrograph shows duodenal mucosa with
complete replacement of the normal epithelium
with goblet cells by gastric foveolar epithelium.
Note the widened, distorted villi and increased
in?ammatory cells within the lamina propria.
62
6. Large intestine
  • ---absorb water and ions
  • ---structure feature
  • a. no villus and no circular plica
  • b. well-developed large intestinal gland
  • c. contain more goblet cells
  • d. taeniae coli longitudinal bunds
  • bag coli

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64
Colorectal Cancer is a malignant neoplasm of the
colon or the rectum. Adenocarcinoma is the most
common type of colon cancer (98 of cases.
Presenting symptoms may be a change in bowel
habits due to bowel obstruction, blood in the
stool, or iron de?ciency anemia. This
photomicrograph shows a moderately differentiated
adenocarcinoma of the colon in?ltrating the
muscularis propria.
65
Crohn Disease a chronic autoimmune in?ammatory
disease of the gastrointestinal tract that may
affect any location, from the oral cavity to the
anus, but mostly involves the distal small
intestine and colon. This image shows colonic
mucosa with depletion of goblet cells,
noncaseating granulomas within the lamina
propria, chronic in?amma-tion, and neutrophils
invading the crypt cells.
66
Comparative of different part of digestive tract
67
Appendix Fewer and shorter
intestinal glands and more lymph tissue
68
Gastrointestinal associated lymphoid tissue (GALT)
69
  • M macrophage MC microfold PC plasma cell

70
  • Endocrine cell

Locationpresent between the epithelial lining
and glands Types Open?Closed
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72
Digestive Tract Review
  • The general structure of digestive tract
  • Histology of the esophagus
  • The microstructure of stomach
  • The small intestinal glands and microvillus
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