Examine these two slides of liver (sample 1 H&E, and sample 2 Masson's trichrome) and the image below.

• Note the anastomosing plates of hepatocytes between the portal tracts and the central venule.
• Identify the vascular sinusoids between the plates of hepatocytes and the endothelial cells lining the sinusoids.
• Identify the scattered, rounded macrophages (Kupffer cells) in the sinusoidal lining.
• Note how the hepatocytes near the portal tract appear different from those near the central vein. This is due to exposure of the hepatocytes to blood with changing levels of oxygen and metabolites as it flows from the portal areas towards the central venule.

Next, carefully examine the ultrastructure of hepatocytes forming a bile canaliculus (asterisk) in the electron micrograph and light micrograph (arrows) images below. Bile is the major exocrine product of the liver. It flows from hepatocytes into the bile canaliculi, into the bile ductules at the portal areas, into the bile ducts, and eventually into the common hepatic duct.

Finally, study figure 16-14 from Junqueira’s Histology 14e to see additional views of important ultrastructural features of the liver that you should be familiar with, including:

• Microvilli projecting from the hepatocytes
• Sinusoids
• The perisinusoidal space (of Disse)
• The bile canaliculi

Now for the gallbladder.