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Digestive glands

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Title: Digestive glands Last modified by: Sky123.Org Created Date: 7/21/2003 9:00:25 AM Document presentation format: (4:3) Company: rAt – PowerPoint PPT presentation

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Title: Digestive glands


1
Digestive glands
2
General outline
  • small digestive glands
  • distributed in the wall of digestive tract
  • esophageal glands, gastric glands and
  • intestine glands
  • large digestive glands
  • outside the wall of digestive tract
  • salivary glands, liver and pancreas

3
Large salivary glands
  • Include parotid, submandibular and
  • sublingual glands
  • are compound tubuloacinar glands
  • are composed of acini and ducts

4
Large salivary glands
5
Acinus
  • acinar epithelium simple
  • cuboidal or pyramidal cells
  • myoepithelial cell
  • basal membrane

Structure
Serous acini Mucous acini Mixed acini
Be divided into
6
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7
Serous acini
  • cytoplasma are deep stained
  • nucleus are spherical in shape and near
  • the base
  • secretion is thin, contains salivary amylase
  • and a little mucus

8
Serous acini and striated duct
9
Mucous acini
  • cytoplasma are light-blue stained
  • nucleus are flattened ovoid shaped and
  • close to the base
  • secretion is thick contains mucoprotein

10
Mucous acini
11
Mixed acini
  • consist of above two kinds of cells
  • demilunes several serous cells are
  • attached eccentrically to the mucous acini

12
Mixed acini
13
Ducts
  • Intercalated ducts

diameter thinnest wall simple low cuboidal
epithelium
14
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15
  • Striated duct (secretory duct)
  • wall simple columnar epithelium the nucleus
  • is near the cell apex cytoplasm is
  • acidpphilic has basal striations
  • EM the basal striations created by
  • membrane infolding and mitochondia
  • reabsorbing sodium and excreting potassium
  • transport water and ions

16
  • ??(duct)

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Intercalated duct
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???
Striated duct
???????? ?????
17
Intercalated ducts and striated ducts
18
  • Interlobular duct

Wall pseudostratified epithelium
  • Main duct

Near its orifice become stratified squamous
epithelium
19
Parotid gland
  • pure serous gland
  • longer intercalated duct
  • secrete 25 of saliva, more salivary
  • amylase, less mucus

20
Parotid gland
21
Submandibular gland
  • mixed gland. Serous acini are more than
  • mixed or mucous acini
  • short intercalated duct, longer striated duct
  • secrete 70 of saliva, less salivary amylase,
  • more mucus

22
Submandibular gland
23
Sublingual gland
  • mixed gland, mucous and mixed acini
  • predominant, more demilune
  • without intercalated duct, obscure striated
  • duct
  • secrete 5 of saliva, most mucus

24
Sublingual gland
25
Pancreas
Exocrine portion
  • the features of the acini
  • a single layer of pyramidal serous cells
  • surrounded by basal lamina, without
  • myoepithelial cells
  • centro-acinar cells the epithelial cells of
  • intercalated duct penetrating into the
  • lumen of the acinus

26
  • the feature of ducts
  • the intercalated duct is long and has branches
  • no striated duct
  • main duct lined by simple columnar
  • epithelium in which a few goblet cells
  • and endocrine cells can be seen

27
  • The functions of exocrine portion

Secret abundant trypsinogen, chymotrypsinogen,
amylase, lipase, sodium bicarbonate and trypsin
inhibitor
28
Pancreas
29
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30
Pancreas ( show centro-acinar cells and
intercalated ducts)
31
Endocrine portion (pancreatic islet)
  • rounded clusters of cells embedded within
  • exocrine pancreatic tissue
  • are divided into three kinds of cells A, B,
  • and D cells
  • fenestrated capillaries are among the
  • cells

32
Pancreas (show pancreatic islet)
33
Endocrine portion
Size number Distribution Function
A cells large 20 Peripheral glucagon
B cells small 75 center insulin
D cells 5 Among A and B cells somatostatin
PP cells pancreatic polypeptide G cells gastrin
Other cells
34
A cells
B cells
D cells
35
Liver
Hepatic plates Sinusoid Central vein
Liver lobule
Interlobular arteries Interlobular
veins Interlobular bile ducts
Portal area
36
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37
Functions of liver
  • bile secretion
  • synthesize protein, glycogen, cholesterin
  • detoxification and inactivation
  • defence
  • hemopoiesis

38
Human liver
Pork liver
39
Liver lobule
  • hepatic plates are composed of a single
  • layer of hepatocytes arranged in radial
  • sinusoid situated between the hepatic
  • plates, forming a complex network
  • central vein occupies the centre of the
  • liver lobule

40
Liver lobule
41
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42
Hepatic plates
43
Hepatic cords and liver sinusoids
44
Hepatocytes
  • polyhedral in shape, eosinophilic cytoplasm,
  • one or two large rounded nuclei with one or 2
  • typical nucleoli
  • EM Mi, RER, SER, Golgi apparatus,
  • lysosomes, microbodies, inclusions

45
  • Mitochondria

provide the energy for the hepatocytes
  • Rough endoplasmic reticulum

synthesize some plasma proteins
  • Golgi apparatus

participate in the formation of bile and
lipoprotein
46
  • Smooth endoplasmic reticulum
  • synthesize bile, triglyceride and LDL
  • metabolism of the lipid, hormones and
  • cholerythrin
  • inactivate steroid hormone
  • biotransformation of some materials
  • detoxification of noxious substances

47
  • Lysosomes
  • actively participate the metabolism of
  • hepatocyte and renewal of organelles
  • play a role in metabolism and transport of
  • cholerythrin
  • storage of iron

48
  • Microbodies

detoxification catalase and peroxidase
reduce the hydrogen peroxide into H2O
  • Inclusions

include glycogen, lipid droplets, pigment
etc These contents vary according to physiologic
state of human body
49
Bile canaliculi
  • between two adjacent hepatocytes
  • the membrane of hepatocyte projects to
  • the lumen, forming many microvilli
  • the cell membranes near the bile canaliculi
  • are firmly bound by junctional complexes

50
Bile canaliculi
51
Liver sinusoid
  • spaces between the hepatic plates
  • irregular in shape
  • composed of only one discontinuous layer of
  • fenestrated endothelial cells, no diaphragm,
  • no basement membrane
  • Kupffer cells are located within the sinusoid
  • cavities

52
  • ??? Hepatic sinusoid

????????
?????,?????,??? ?,???
??
??
????,?????????? ????
????
  • ??? ?????????

(Disse ?)
53
Kuffer cells in liver sinusoid
54
Liver sinusoid and space of Disse
55
Space of Disse
  • separates the endothelium from the
  • hepatocytes
  • contains some reticular fibers and fat-storing
  • cells

56
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57
???????
58
Portal space
  • the connective tissue separating the lobules
  • including

Interlobular arteries Interlobular
veins Interlobular bile ducts
59
Portal spaces
60
Blood circulation
portal V.
interlobular V.
(functional vessel)
sinusoids
central V.
hepatic A.
interlobular A.
sublobular V.
(nutrient vessel)
hepatic V.
61
??????
?V ???V
??? ??V ???V
?A ???A
?V
??V
62
Blood vessels of liver
(prepared Chinese ink injection through portal
vein)
63
Discharge way of bile
Bile canaliculi
Herings canals
Interlobular bile ducts
Gallbladder
Hepatic duct
Common bile duct
Cystic duct
duodenum
64
??????
???
???
??
?????
?????
???
????
???
??
65
Gallbladder
Simple columnar Epi. , no Goblet cells Laminar
propria C.T.
  • mucosa
  • muscle layer composed of an inner circular,
  • an outer longitudinal layers of smooth muscle
  • adventitia most are fibrosa, some are serosa

66
Gallbladder
67
?????????????
Mi?? RER?????(???????????) SER????????????????
???? Golgi???????????? lysosome
??????????????? ????
68
????
  • ??

??????,??,???,??? ???,??????
  • ??

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