LIVER. HISTOLOGY PORTAL VEIN CENTRAL VEIN HEPATIC ARTERY BILE DUCT ZONE 1 ZONE 2 ZONE 3.
Functional histology of liver
description
Transcript of Functional histology of liver
![Page 1: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/1.jpg)
Functional histology of liver
![Page 2: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/2.jpg)
Functions of the liver
![Page 3: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/3.jpg)
Production of circulating plasma proteins Albumins Lipoproteins [VLDLs, LDLs, HDLs] Glycoproteins e.g. transferrin Prothrombin Fibrinogen Non-immune globulins
![Page 4: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/4.jpg)
Vitamin storage and conversion Vitamin A [retinol] Vitamin D [cholecalciferol] Vitamin K
![Page 5: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/5.jpg)
Degradation of drugs and toxins2 processes1. Oxidation2. Conjugation with glucoronic acid,
glycine and taurine [products become water soluble and removed by kidneys]
![Page 6: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/6.jpg)
Involvement in metabolic pathways Glycogenolysis Consumption of fatty acids by beta
oxidation for energy Production of ketone bodies – used
as fuel by other organs Urea synthesis Synthesis and conversion of non-
essential amino acids
![Page 7: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/7.jpg)
Bile production
Liver converts substrates delivered by blood from digestive tract, pancreas and spleen
Some of these products are involved in the production of bile
![Page 8: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/8.jpg)
Bile contains conjugated and degraded waste products that are returned to intestine for disposal, as well as substances that bind to metabolites in the intestine to aid in absorption
![Page 9: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/9.jpg)
Modification and structure and function of hormones Conversion of Vitamin D to 25-
hydroxycholecalciferol Conversion of Thyroxine to its
biologically active form, triiodothyronine
Modification of action of Growth hormone by Growth hormone releasing hormone [GHRH] produced by liver
![Page 10: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/10.jpg)
Degradation of insulin and glucagon
![Page 11: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/11.jpg)
STRUCTURAL ORGANISATION
Parenchyma, consisting of organised plates of hepatocytes, which are normally one cell thick and separated by sinusoidal capillaries. In children, the liver cells are arranged I plates 2 cell thick
Connective tissue stroma, that is continuous with the fibrous capsule of Glisson. Blood vessels, nerves, lymphatic vessels and bile ducts travel with the stroma
![Page 12: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/12.jpg)
Sinusoidal capillaries (sinusoids), the vascular channels between plates of hepatocytes
Perisinusoidal spaces (spaces of Disse), between sinusoidal epithelium and hepatocytes
![Page 13: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/13.jpg)
![Page 14: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/14.jpg)
![Page 15: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/15.jpg)
Classic hepatic lobule
![Page 16: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/16.jpg)
Roughly hexagonal mass of tissue Consists of stacks of anastomosing
plates of hepatocytes, one cell thick, separated by the anastomosing system of sinusoids that perfuse the cells with the mixed portal and arterial blood.
![Page 17: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/17.jpg)
Each lobule measures about 2.0 × 0.7 mm.
At the center of the lobule is a relatively large venule, the terminal hepatic venule (central vein)into which the sinusoids drain.
![Page 18: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/18.jpg)
The plates of cells radiate from the central vein to the periphery of the lobule, as do the sinusoids.
At the angles of the hexagon are the portal areas (portal canals), loose stromal connective tissue characterized by the presence of the portal triads..
![Page 19: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/19.jpg)
This connective tissue is ultimately continuous with the fibrous capsule of the liver.
The portal canal is bordered by the outermost hepatocytes of the lobule
![Page 20: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/20.jpg)
The blood vessels and draining branches of the bile duct system course together in a relationship called portal triad.
This is a misnomer, as one or more lymphatic vessels always travel with the vein artery and bile duct
![Page 21: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/21.jpg)
![Page 22: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/22.jpg)
![Page 23: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/23.jpg)
![Page 24: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/24.jpg)
![Page 25: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/25.jpg)
![Page 26: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/26.jpg)
![Page 27: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/27.jpg)
![Page 28: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/28.jpg)
At the edges of the portal canal, between the connective tissue stroma and the hepatocytes, is a small space called the space of Mall.
This space is thought to be one of the sites where lymph originates in the liver.
![Page 29: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/29.jpg)
In some species, e.g., the pig, the classic lobule is easily recognized because the portal areas are connected by relatively thick layers of connective tissue.
![Page 30: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/30.jpg)
In some species, e.g., the pig, the classic lobule is easily recognized because the portal areas are connected by relatively thick layers of connective tissue.
![Page 31: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/31.jpg)
![Page 32: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/32.jpg)
In humans, however, there is normally very little interlobular connective tissue, and it is necessary, when examining histologic sections of liver, to draw imaginary lines between portal areas surrounding a central vein to get some sense of the size of the classic lobule
![Page 33: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/33.jpg)
Kupffer cells
Belong to MPS- derived from monocytes SEM and TEM show that they form part
of the vessel lining Previously they were described as lying
on the luminal surface of endothelial cells. This was probably based on the fact that processes of Kupffer cells occasionally overlap endothelial processes on the luminal side
![Page 34: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/34.jpg)
They do not form junctions with endothelial cells
They form 15% of liver cell population- most are located in the periportal region
![Page 35: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/35.jpg)
![Page 36: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/36.jpg)
![Page 37: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/37.jpg)
![Page 38: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/38.jpg)
Functions
Metabolisation of aged RBCs and digestion of Hb
Secretion of proteins related to immunologic processes
Destruction of bacteria
![Page 39: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/39.jpg)
In the fetal liver, the spaces between blood vessels and hepatocytes contain blood-forming cells.
In cases of chronic anaemia in the adults, these cells may reappear in the perisinusoidal spaces
![Page 40: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/40.jpg)
Perisinusoidal space/ space of Disse
lies between basal surface of endothelial cells and Kupffer cells- site of exchange of materials between blood and liver cells
Small ,irregular microvilli from hepatocytes project into this space, which increase the available surface area for exchange of materials 6 times
![Page 41: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/41.jpg)
![Page 42: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/42.jpg)
![Page 43: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/43.jpg)
![Page 44: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/44.jpg)
The portal lobule
emphasizes the exocrine functions of the liver
Morphologic axis of the portal lobule is the lobule is the interlobular bile duct of the portal triad of the “classic” lobule.
Its outer margins are imaginary lines drawn between the three central veins that are closest to that portal triad.
![Page 45: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/45.jpg)
![Page 46: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/46.jpg)
These lines define a roughly triangular block of tissue that includes those portions of three classic lobules that secrete the bile that drains into its axial bile duct.
This concept allows a description of hepatic parenchymal structure comparable to that of other exocrine glands
![Page 47: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/47.jpg)
The liver acinus
Structural unit that provides the best correlation between blood perfusion, metabolic activity, and liver pathology
Lozenge shaped and represents the smallest functional unit of the hepatic parenchyma.
The short axis of the acinus is defined by the terminal branches of the portal tried that lie along the border between two classic lobules.
![Page 48: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/48.jpg)
The long axis is a line drawn between the two central veins closest to the short axis.
In a two-dimensional view the liver acinus occupies parts of adjacent classic lobules.
This concept allows a description of the exocrine secretory function of the liver comparable to that of the portal lobule.
![Page 49: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/49.jpg)
![Page 50: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/50.jpg)
The hepatocytes in each liver acinus are described as being arranged in three concentric elliptical zones surrounding the short axis
![Page 51: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/51.jpg)
Zone 1 is closest to the short axis and the blood supply from penetrating branches of the portal vein and hepatic artery.
This zone corresponds to the periphery of the classic lobules.
![Page 52: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/52.jpg)
Zone 3 is farthest from the short axis and closest to the terminal hepatic vein (central vein). This zone corresponds to the most central part of the classic lobule that surrounds it
Zone 2 lies between zones 1 and 3 but has no sharp boundaries
![Page 53: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/53.jpg)
![Page 54: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/54.jpg)
![Page 55: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/55.jpg)
![Page 56: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/56.jpg)
![Page 57: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/57.jpg)
![Page 58: Functional histology of liver](https://reader036.fdocuments.net/reader036/viewer/2022081503/568166db550346895ddaff22/html5/thumbnails/58.jpg)