120 



CHOLINE 



fat storage and fibrosis. From here, trabeculae can extend only in directions 

 toward neighl)oring central veins or conducting portal veins; otherwise they 

 would encroach more directly on portal regions (Figs. 15 and 16). Thus, 

 extension of trabeculae in accordance with the non-portal principle eventu- 

 ally results in fibrotic replacement in regions around large portal triads 

 which are anatomically, l)ut not functionally, periportal. By this process, 

 considerable areas along large portal veins become surrounded, often in 



Fig. 18. The Held imincdiately below the white arrow in Fig. 17 is enlarged in 

 this photomicrograph. A small bile duct is shown in cross section, and below it, but 

 less clearl}^ shown, is a small terminal portal venule containing one or two red 

 cells. There is no fibrosis present, and with regard to these functionally periportal 

 regions, the fibrosis is non-portal. X800. 



eccentric fashion (Fig. 16), by trabeculae of condensed hepatic stroma. But 

 even in relatively ad^'anced stages of cirrhosis in rats, the terminal portal 

 venules at the points where they ramify into sinusoids remain almost com- 

 pletely free of fibrosis. This may not be readily appreciated in thin micro- 

 sections, for these venules are small and often missed by the plane of the 

 section. Furthermore, if the parenchyma surrounding them be fatty, they 

 are even more difficult to find under the lower powers of the microscope. 

 If the observer is not aware of their importance as landmarks in orienting 

 the lobular distribution of lesions, he may completely overlook these small 

 vessels. By contrast, he may be readily misled by the large conducting 



