286 



HISTOLOGY 



capillaries, or they may be intercellular branches of an axial capillary 

 which is in the plane of the printed page. In some places the bile capil- 

 laries completely encircle an hepatic cell, forming " true meshes" (Fig. 280). 

 They may form larger meshes due to the anastomosis of trabeculae. Occa- 

 sionally a bile capillary is in relation with three surrounding hepatic cells, 

 or even more, thus resembling the lumen of an ordinary gland-tubule. 



In addition to intercellular capillaries there are said to be intracellular 

 branches, several of which may penetrate the protoplasm of a single cell 

 and end in knobs, as shown by the Golgi method. Since neighboring 

 capillaries may be free from these branches, they are regarded as tempo- 





FIG. 281. SECTION OF THE LIVER OF A SALAMANDER (Necturus). X 380. 

 a, Endothelial cell; b, endothelial reticulum; c, blood vessel; d, bile capillary; e, red corpuscle; f, hepatic cell. 



rary phases of functional activity, accompanying the discharge of secretion. 

 They have been reported as forming baskets within the protoplasm, 

 similar to those found in parietal cells of the stomach. 



The bile capillaries and their branches are generally separated from 

 the lining of the blood vessels by an appreciable portion of the hepatic cells 

 (cf. Figs. 280 and 281). Pathologically they may extend nearer the vessels 

 and may rupture, so that the bile escapes into the perivascular tissue and 

 is distributed over the body, causing jaundice. 



Endothelium and Perivascular Tissue. The endothelium of the capil- 

 liform sinusoids which border upon the hepatic trabeculas is specially modi- 

 fied; it is well shown in the coarse-grained liver of Nectunis (Fig. 281), 

 but the same form occurs in the human liver. The endothelial cells, which 

 are phagocytic, produce a network of reticular fibers toward the hepatic 

 cells (Fig. 282). The reticulum contains no elastic elements, and the 

 only cell bodies associated with it are those of the endothelium. In the 

 reticular meshworkin the embryo, erythroblasts multiply in great numbers. 



