histology of liver by aravindh dpi

HISTOLOGY OF LIVER

IDENTIFICATION POINTS Hepatic lobules with central vein Radiating hepatic cord cells Portal triad

STRUCTURE Stroma thin layer of reticular fibres surrounding the hepatic cord cells

and sinusoids. acts like frame work of liver cells parenchyma repeated units of hepatic lobules forms whole liver

parenchyma hepatic lobules hexagonal or polygonal in shape covered by thin connective tissue called inter lobular

septum1. There is a central vein at the center of hepatic lobule and

hepatic cord cells radiate from the central vein.2. In between two hepatic cords cells there are sinusoids made

up of fenestrated endothelium and von Kupffer cells.3. Kupffer cells act as macrophages and destruct the old rbc’s

thus form a reticulo endothelial system.

Bile canaliculi in the microscopy of liver each

hepatocyte is connected to another by extension of cytoplasmic threads through minute canals called bile canaliculi.

Perisinusoidal space of disse space found between endothelium of

sinusoids and hepatic cords cells. It contains reticular fibres Microvilli of hepatic cords and Lipocytes and lto cells or stellate cells Lto cells rich in fat with vitamin A.

SPACE OF DISSE

LIVER LOBULES Liver lobules The three types of liver lobules are the classical lobules, portal lobules, and the

hepatic acinus (acinus of Rappaport). I.Classical liver lobule: In this concept, blood flows from the

periphery to the center of the lobule into the central vein.

Bile, manufactured by liver cells, enters into small intercellular spaces, bile canaliculi, located between hepatocytes, and flows to the periphery of the lobule to the interlobular bile ducts of the portal areas.

2)PORTAL LOBULES all hepatocytes that deliver their bile to aparticular interlobular bile duct.3)Hepatic acinus (acinus of Rappaport) : It is viewed as three poorly defined, concentric regions of hepatic parenchyma surrounding a distributing artery in the center. The outermost layer, zone 3,extends as far as the

central vein and is the most oxygen-poor of the three zones. The remaining region is divided into two equal zones

(1 and 2); zone 1 is the richest in oxygen.

HEPATOCYTE Hepatocytes are polyhedral cells having

one or two spherical nuclei with nucleoli. Cytoplasm is eosinophilic and contains

mitochondria, RER,SER AND GOLGI APPARATUS ARE

WELL DEVELOPED Out of six or more surfaces at least two

surfaces of each hepatocyte are in contact with wall of sinusoids through space of disse,facillitate exchange of materials,.

PORTAL AREA

PORTAL TRIAD