Liver pancreas

1. Ass. Prof. Demianenko I.A. Department of Histology MA CFU

LIVER
PANCREAS

2.

3. Liver -

Liver is the largest gland of organism.
It is mixed gland :
exocrine portion secrets bile into the
intestine (duodenum),
endocrine secrets substances of synthesis
or metabolic products into the blood.

4. Development of liver

Starts
from the 3-d week of
embryogenesis as enfolding of
endoderm of primitive gut (hepatic
diverticulum) into the mesenchyme of
mesenterium.
Parenchyma is derived from endoderm,
stroma – from mesenchyme.
.

5. Hepatic diverticulum

Subdivides
into cranial and caudal
portions
Cranial portion forms germs of liver
and hepatic duct
Caudal portion forms germs of gall
bladder and bile duct

6. Development of liver

7.

8. Blood supply of liver

Portal vein enter the liver hilum with the blood
from DS organs. It contains all nutrients, toxic and
biologic active substances after absorbtion in
intesting.
In the liver destruction of them occur and harmless
substances enter the bile.
Also, hepatic artery bring blood into the liver from
aorta.

9. Blood supply of liver lobule

10. Basic functions:

1. Participation in all metabolic processes
2. Render harmless of metabolic products
3. Inactivation of hormones, poisons,
some methabolic products
4. Participation in synthesis of glycogen,
blood plasma proteins

11.

5. Synthesis of bile
6. Accumulation of vitamins A,D,E,K
7. Participation in cholesterine exchange
8. Hemopoiesis in embryonic period

12. Structural-functional unit of liver

Classic
liver lobule is hexogonal in
shape and consists from hepatocytes
plates and sinusoidal capillaries
between them in the direction of lobule
center (central vein)

13.

14.

15. Liver lobule

16. Hepatocytes plate

Consists of two rows of hepatocytes.
There are bile canaliculi between
hepatocytes.
There are sinusoidal capillaries between
neighboring hepatocytes plates.
There is Disse space between
hepatocytes plate and capillary
endothelium

17. Structure of liver lobule with hepatocytes plates, triade and sinusoidal capillaries

18. Hepatocytes plate

Consists of two rows of hepatocytes.
There are bile canaliculi between
hepatocytes.
There are sinusoidal capillaries between
neighboring hepatocytes plates.
There is Disse space between
hepatocytes plate and capillary
endothelium

19. Hepatocytes plates, portal triade, sinusoidal capillaries and cells of liver

20. Hepatocytes plates and sinusoidal capillaries

21. Stroma of liver lobules

22. Stroma

Consists of thin layers of connective tissue
with triads, sublobular veins, lymphatic
vessels and nerve fibers.

23. Triade: hepatic artery (А), portal vein (V), bile duct (В)

24. Triade

25. Connective tissue trabecular in animals liver

26. Hepatocytes

form 80% of all liver cells
are irregular in shape
have one (75% of cells) or two (25%) nuclei
nuclei are spherical in shape with 1-2
nucleoli

27. Cytoplasm of hepatocyte

Contains numerous mitochondria
lysosomes, peroxisomes, RER, SER ,
Golgi apparatus, lipids droplets, glycogen

28. 1- Disse space 2 – endothelial cell of sinusoidal capillary

29. Cells of sinusoidal capillary

1)
Endothelial cells (50%)
form sinusoidal lining. Have pores or
clefts.
2) Stellate macrophages - Kupffer cells
(20-25%)
are in the clefts between endothelial cells
or on their surface

30. Kupffer cells

Conteins numerous lysosomes in cytoplasm and
have high phagocytotic activity
Functions: Clean blood from microorganisms,
antigens, toxins, damaged erythrocytes

31. Kupffer cells

32.

3) Ito cells ( 20-25%) of cells of sinusoids,
are in Disse space
Their cytoplasm contains large lipid drops with
vitamin A
In pathologic cases they become active and
produce collagen, that leads to fibrosis of liver

33.

4) Pit-cells (5%) of cells of sinusoids,
are in sinusoid lumen or in Disse space.
They are similar with NK-cells (natural
killars)
Participates in cellular immune response,
especially active against tumor cells

34.

35. Sheme of liver ultrastructure

1- sinusoidal capillary
2- endothelial cell
3- clefts in capillary
4- Kupffer cell
5- space of Disse
6- reticular fibers
7- microvilli of hepatocytes
8- hepatocytes
9- bile canaliculus
10- Ito cells
11- lipid inclusions in Ito cell
12- erythrocytes in capillary

36. Sheme of sinusoidal capillary ultrastructure

1- Kupffer cell
2- endothelial cell
3- space of Disse
4- reticular fibers
5- Ito cell
6- pit-cell (NK-cell)
7- tight junction of
hepatocytes
8- desmosome
9- bile capillary

37. Structural units of liver

Classic lobule
Portal lobule
Hepatic acinus

38.

39.

40. Gall bladder

Wall of gall bladder consists of 3 layers:
1) Mucosa
2) Muscularis
3) Serosa

41. Gall bladder wall

42. PANCREAS

Mixed gland
97% of gland volume-
Exocrine portion (cells of acini) - produce
pancreatic juice with digestive enzymes.
3% of gland volume-
Endocrine portion (cells of
islets of Langerhans)- secrets hormones.

43. PANCREAS develops from dorsal enfolding of epithelium of primitive gut into underlining mesenchyme. Epithelial parenchyma

derived from
endoderm.
Connective tissue stroma derived from
mesenchyme.

44. Development of pancreas

45. PANCREAS

46. PANCREAS

47. Exocrine portion of pancreas

Makes up 97% of the volume of
pancreatic lobules.
It forms compound tubulo-alveolar serous
gland, which consists of secretory portions
(acini) and system of ducts

48. Acinus

Is spherical or elongated in shape and tight
lumen
It consists of 2 types of cells –
acinar cells and centroacinar cells

49. Acinus

50. Acinar cells

Large pyramidal cells
Their basal portion contains numerous
organelles of synthesis –
homogen (basophilic) zone
Their apical portion contains accumulation
of large secretory granules with enzymes
– zymogen (oxyphylic zone)

51. Cells of acinus

52. Acinar cells in acini

53. Secretory granules enzymes

Trypsin, chymotrypsin, amylase, elastase,
DNase, RNase and others responsible to
digestion of food.
Enzymes activates only in duodenum, therefore
pancreas is protected from autodigestion
Activation of enzymes happens in the case
of acute panceatitidis.

54. Centroacinar cells

Small, flattened, stellate cells with pale
cytoplasm and not numerous organelles.
Location – in the center of acinus.
Function – regulation of pH of pancreatic juice

55. System of ducts

Intercalated duct
Intralobular duct
Interlobular duct
Main and accessory ducts

56. Pancreas

57. Endocrine portion - Langerhans islets

Endocrine portion Langerhans islets
consists of:
accumulations of endocrine cells
fenestrated capillaries
reticular and nerve fibers I in interstitium

58. Langerhans islet

59. Endocrine cells and capillaries

60. Langerhans islet

61. Endocrine cells have secretory granules with hormones

А-cells – 20-25% from all endocrine cells, in
peripheral area of islet. Granules are oxyphilic.
Secrets hormone glucagon, which increase
level of glucose in the blood due to breakdown
of glycogen.

62. В-cells

60-70% from all endocrine cells, in the center of
islet. Granules are basophilic.
Secrets hormone insulin.
Insulin promotes the absorption of glucose by
tissue cells.
It decrease level of glucose in blood.

63. А and В cells

64. Insulin synthesis by B-cells

65.

66. D-cells

5-10% from all endocrine cells, in
peripheral area of islet.
Secrets hormone somatostatin, which
inhibits activity of acinar,A and B-cells.

67. РР- cells

2-5%
from all endocrine cells, in
peripheral area of islet.
Secrets hormone pancreatic
polypeptide, which stimulate activity of
pancreatic acinar cells.