HA3 shows a portal canal and its constituents: portal vein, hepatic artery, bile duct, and lymphatic (V, A, B and L in HA3). The autonomic nerve branches require a special stain and higher magnification to be visible. Bile ducts are lined by simple cuboidal epithelium, and the hepatic "artery" is usually an arteriole (with less than 5 layers of vascular smooth muscle). Note that more than one example of each may be present in each portal canal due to branching of the vessels of plane of section.