1. بسم الله الرحمن الرحيم

2. LIVER,
GALL BLADDER,
PANCREAS

3. LIVER

4. PIG’S LIVER LOBULES

5. HUMAN LIVER LOBULES

6. PORTAL AREA (PORTAL TRIAD)

7. PORTAL AREA (PORTAL TRIAD)
Bile Duct
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11. LIVER 1- Stroma: a- Capsule: Glisson’s Capsule.
b- Septa (absent in human) &
Portal areas (Portal triads)
(Portal tracts)
(Portal spaces) (Portal canals)
c- Network of reticular fibers.
2- Liver lobules ( classic hepatic lobules )

12. CLASSICAL LIVER LOBULE (classical hepatic lobule)
It is formed of a polygonal mass of tissue ,
With portal areas at the periphery &
Central (centrolobular) vein in the center.

13. Borders of the classical liver lobule
1- Septa: C.T. septa (e.g. in pigs).
2- Portal areas (Portal triads):
Are located in the corners of the lobules
(usually 3 in No.).
Contents of portal area:
a- C.T.
b- Bile ducts ( interlobular bile ducts ).
c- Venule ( Branch of portal vein).
d- Arteriole ( Branch of hepatic artery).
e- Lymphatics.
f- Nerves.

14. CONTENTS OF THE CALSSICAL LIVER LOBULE
1- Anastomosing plates of hepatocytes.
2- Liver sinusoids (hepatic blood sinusoids):
In between the plates.
3- Spaces of Disse (perisinusoidal spaces of Disse).
4- Central vein ( Terminal hepatic venule ).
5- Bile canaliculi.
6- Limiting plate of hepatocytes & space of Moll.

15. HEPATOCYTES (L/M)

16. HEPATOCYTES (L/M) *Are grouped in interconnected plates.
*Liver sinusoids are located in the spaces between these plates.
*Are polyhedral in shape.
*Nucleus: 1 or 2, vesicular, 1 or 2 nucleoli,
May be polyploid nucleus.
*Cytoplasm: acidophilic? Mitochondria ++++,
sER.
With basophilic bodies? rER.
Glycogen.
*Limiting plates & space of Moll.

17. HEPATOCYTE ( E/M )
(Fascia Type)
(Not mentioned in Gartner)

18. HEPATOCYTE ( E/M )

19. HEPATOCYTE ( E/M )

20. HEPATOCYTE ( E/M )

21. HEPATOCYTES (E/M) Surfaces (Plsmalemma has two domains 1 & 2):
1- Sinusoidal domains (surfaces):
lines space of Disse,
contains many microvilli.
2- Lateral (Intercellular) Domains (surfaces).
(3) Canalicular surface: ????????????
part of lateral (intercellular) surface with bile canaliculus.

22. 1- Junctional complexes:
HEPATOCYTES (E/M)
Junctions:
1- Junctional complexes:
Tight Junction (Fasciae occludentes), adherent Junction (?????)&
Desmosome(???????).
2- Gap junctions.

23. Inclusions (Deposits):
HEPATOCYTES (E/M)
Organelles:
1- Mitochondria: ++++
2- ER (sER & rER): abundant.
3- Golgi complex.
4- Lysosomes.
5- Peroxisomes.
Inclusions (Deposits):
1- Glycogen 2- Lipid 3- Lipofuscin (old age)

24. LIVER SINUSOIDS & SPACE OF DISSE

25. LIVER SINUSOIDS & SPACE OF DISSE

26. FENESTRATED ENDOTHELIUM

27. LIVER SINUSOIDS (1) ENDOTHELIAL CELLS:
Fenestrated (sieve plates: are clusters of fenestrae) & discontinuous →
Free passage of plasma.
Basal lamina is absent.
Supported by a delicate sheath of
reticular fibers of space of Disse.
(2) Kupffer cells:
Are macrophages.
Are stellate in shape.
Are found on the luminal surface of
the endothelial cells, within the sinusoids.
Function: phagocytosis.

28. SPACE OF DISSE (PERISINUSOIDAL SPACE)
Contents:
1- Fat-storing cells (hepatic stellate cells)
( Ito cells): contain vitamin A-rich lipid.
form reticulin.
2- Reticular fibers (type III collagen).
3- Plasma of blood.
4- Microvilli of hepatocytes.
5- Pit cells: may be natural killer cells.

29. BILE CANALICULI

30. Bile canaliculus

31. Bile canaliculus

32. BILE CANALICULUS The 1st. Portion of bile duct system.
It is limited only by the cell membranes of 2 hepatocytes.
It has few microvilli in its interior.
The cell membranes of the 2 hepatocytes
near the canaliculus are joined by tight junctions (fasciae occludentes).

33. BILIARY PASSAGES 1- Bile canaliculi.
2- Cholangioles: are lined with hepatocytes, low cuboidal cells
& occasional oval cells.
2- Canals of Hering: Are parallel to inlet arterioles & inlet venules.
Are lined with low cuboidal cells
with some ovoid cells.
3- Interlobular Bile ducts: * in the portal areas
* simple cuboidal
(or simple columnar????????).
4- Right & left Hepatic ducts.

36. BLOOD SUPPLY (B) Arterial system:
(A) Portal vein system:
1- Portal venules: in portal areas.
2- Distributing veins (perilobular venule): at the periphery of the lobule.
3- Inlet venules.
4- Sinusoids.
5- Central vein.
6- Sublobular vein.
7- Collecting veins.
8- Two hepatic veins.
(B) Arterial system:
1- Interlobular arteries ( hepatic arterioles of portal areas ).
2- Distributing arteries (or arterioles).
3- Inlet arterioles.

37. THE 3 CONCEPTS OF LIVER LOBULES
1- Classical hepatic lobule
2- Portal lobule
3- Hepatic acinus (acinus of Rappaport)

38. PIG’S LIVER LOBULES

39. LIVER ACINUS

40. LIVER ACINUS

41. LIVER ACINUS

42. LIVER REGENERATION It is due to:
1- Replicative capability of hepatocytes.
2- In severe hepatotoxicty:
Mitotic activity of the oval cells in the wall of cholangioles and canals of Hering.
N.B. Many of regeneration factors are released by Ito cells in the space of Disse.

43. GALL BLADDER

47. GALL BLADDER Mucosa: has abundant folds:
1- Simple columnar epithelium:
a- clear cells b- brush cells.
contain few mucinogen granules.
2- Lamina propria: vascularized Loose C.T.
N.B. Tubuloacinar mucous glands in the
neck of G.B. → secrete most of the
mucus present in the bile.
(2) Muscle layer: SMF( Mostly oblique, others are longit.)
(3) Serosal adventitia.

48. PANCREAS

49. EXOCRINE PORTION Of Pancreas
Stroma: capsule, septa & reticular fibers.
Pancreatic acini:
Acini with centroacinar cells.
No myoepithelial cells.
(C) Duct system:
Centroacinar cells, intercalated ducts (low cuboidal),
intralobular ducts (are NOT prominent ), interlobular
N.B. No striated ducts

50. PANCREAS

51. PANCREAS

52. Pancreatic acinus & Centroacinar cells

53. PANCREAS

54. PANCREAS

55. PANCREAS

57. ISLETS OF LANGERHANS L/M: 1- fine capsule of reticular fibers.
2- cords of polygonal or rounded cells
separated by a network of blood capillaries.

58. Cells of islets of Langerhans
1- Alpha (α) cells: 20%, glucagon.
2- Beta (ß) cells: 70%, insulin.
3- Delta cells: %, somatostatin.
4- PP cells (F cells): 1%, pancreatic polypeptide.
5- G cells: %, Gastrin.

59. PANCREAS

60. ISLET OF LANGERHANS

61. ISLET OF LANGERHANS

62. ISLET OF LANGERHANS

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