BLOODVESSELS OF THE KIDNEY. 



101 



vessels of all the groups of capillaries given off from the ad- 

 joining vasa efferentia communicate with each other, a continu- 

 ous capillary plexus is formed, extending through the entire 

 cortex. This plexus, however, does not, like the cortex itself, 

 form a distinct layer; but is continuous, by means of the 

 plexuses which surround the medullary rays, with the capillary 

 system of the medulla. 



The meshes of the cortical plexus distributed over the tortu- 

 ous portion of the tubules are narrow, and more or less circular 

 in form ; those on the other hand which traverse the medullary 

 ray are wider, and elongated in the direction of the course of 

 the tubules. The capillaries composing this plexus are never 



Fig. 153. 



Fig. 153. Diagrammatic representation of the bloodvessels in the 

 substance of the cortex of the kidney, m, Region of the medullary 

 ray ; 6, region of the tortuous portion of the tubules ; a i, arteria 

 interlobularis ; v i, vena interlobularis ; v a, vas afferens glomeruli ; 

 v e, vas efferens glomeruli ; g I, glomerulus ; v z, venous twig of the 

 interlobular vein. 



adherent to the urinary tubules ; lacuniform spaces, frequently 

 filled with fluid, always intervening between the walls of the 

 blood and urinary vessels. 



From the capillaries just described, minute veins originate 

 at small distances from each other, which quickly coalesce to 

 form larger trunks. In the most external layers of the cortex, 

 which contain no glomeruli, the coalesence of the smaller veins 



