Microscopic picture : The liver contains only two types of cells, the hepatocyt( and kupffer cell, but has a complex vascular supply and excretory sy! em. The unit of liver composition is called lobule or acinus Gelman, 0 P76) which is based on a central hepatic vein and its surrounding liver' gills. The hepatocytes (liver cells) comprise 60% of the liver and the are polygonal in shape and about 30 micron in diameter, having s igle nucleus or, less often multiple. Ifs life span is about 150 6, ; in experimental animals. The hepatocyte has 3 surfaces, one facin ; the sinusoids and space of Disse, the second facing the canaliculus an the third facing neighbouring hepatocyte. There is no basement meml -ane and the wall of the sinusoids consist of endothelial and phagocytic yells of the reticuloendothelial system. The flat components are knot n as kupffer cells.