LIVER (slides 137,139,140 and 141)
Now look at slide 139 of rat (or cat) liver, which is similar in appearance to human liver. Without the connective tissue boundaries of the pig, the lobules are not nearly so well defined. In low power, however, search for central veins and portal areas as before and note the general impression of radiating cords of cells within each lobule. At higher magnification look for the same features as before. Perhaps sinusoids of Kupffer cells or portal canal structures are clearer in this slide than in your last one. Also, notice the evidence of stored glycogen particles in the hepatic parenchymal cells. These cells are often binucleate and have prominent nucleoli.
Since this section has been preserved in methacrylate, the parenchymal cells are unusually clearly outlined. At high magnification, follow some cell membranes as they abut neighboring cells and look for tiny, pin hole sized channels with no further lining, the bile canaliculi, in which the secreted bile flows to ultimately reach the bile ducts in the portal areas. In what direction is the bile flowing within the "classical" hepatic lobule as defined here? Learn now bile canaliculi look in electron microscopy.