LIVER. 



227 



\ 



Bile capillaries. 



^ ' 



Sinusoids. , 



FIG. 258. FROM A RABBIT'S LIVER. X 570. 

 The cells I, 2, a and b, are cut in halves; their four 

 bile capillaries (including I and II) may be in- 

 tercellular branches of trabecular bile capil- 

 laries shown in the group 3, 4, c and d. The 

 latter are seen in surface view, the plane of sec- 

 tion there being between the cells. The actual 

 arrangement can be determined only by 

 reconstruction. 



regard cell boundaries; this is because they lie in intercellular spaces turned 



toward the observer, the cells beneath presenting an uncut surface. Some 



times (as at x] a lumen occurs at the angle where three hepatic cells meet, 



but usually sinusoids are found at the corners of the cells and as seen in the 



figure, a lumen tends to be placed 



as far from the blood vessels as 



possible. 



A bile capillary, as the lumen 



is called, follows the trabeculae, 



branching and anastomosing as 



they do (Fig. 254). Between the 



hepatic cells, the bile capillaries 



send off branches at right angles. 



These intercellular capillaries are 



similar in diameter and structure 



to the trabecular capillaries. They 



are unbranched and end blindly 



before reaching the vascular sur- 

 face of the cells (Fig. 254). In 



cases of pathological obstruction 



of the bile ducts, however, the intercellular capillaries are said to be 



prolonged to that surface and to rupture, so that bile enters the tissue 



spaces and the vessels, producing jaundice. 



Intracellular bile capillaries also occur; several have been found to 



extend from the trabecular capillary into a single hepatic cell. As seen in 



Golgi specimens they may termi- 

 nate in knobs interpreted as vacu- 

 oles of secretion (Fig. 259). Since 

 neighboring capillaries are free from 

 these branches, the intracellular 

 capillaries are regarded as phases of 

 functional activity, accompanying 

 the discharge of secretion. They 

 have been reported as forming bas- 

 kets similar to the secretory capil- 

 laries of parietal cells. In studying 



intracellular capillaries, care must be taken to exclude surface views of 



intercellular forms. 



Sinusoids and perivascular tissue. The endothelium of the sinusoids 



is separated from the hepatic cells by a thin layer of reticular tissue. With 



special methods this tissue is seen to consist of innumerable fine libers free 



FIG. 



Bile capillaries 

 without knobs. 



Bile capillaries 

 with knobs. 



'259. FROM A GOLGI PREPARATION OP 

 THE LIVER OP A DOG. X 490. 



