Liver - Overview

Click on images for full-size photographs

The liver of the mouse consists of four main lobes with a variable lobation pattern. In some inbred mouse strains (e.g., BALB/c) hepatocellular fatty change is normal. The fibrous capsule of the liver projects connective tissue septa into the liver tissue, dividing the liver lobes into indistinct lobules with the central vein (a tributary of the hepatic vein) in the middle and at the corners the portal triad (consisting of branches of the hepatic artery, the portal vein, and the bile duct). The liver parenchyma consists of hepatocytes, large polygonal cells with large central nuclei, arranged in cords. Hepatocellular polykarya and megalokarya (and thus polyploidy) are normal in the mouse. In between the hepatocyte cords are sinusoids lined by fenestrated endothelium. Located in the sinusoids and associated with the endothelial lining are the Kuppfer cells, liver-resident macrophages. The apical surfaces of adjacent hepatocytes form the bile canaliculi, which join to form bile ducts lined by cuboidal epithelium.

The 4X micrograph shows part of a liver lobe, including a portal triad and several central veins. The 10X and 20X micrographs present, in increasing detail, the elements of the portal triad, i.e., the bile duct, the hepatic artery, and the portal vein. The 20X and 40X micrographs depict the components of the liver parenchyma, the hepatocytes and Kupffer cells, in detail.