THE URINARY ORGANS. 



157 



FIG. 132. 



parallel to the bases of the latter, and, therefore, to the convex 

 surface of the organ, and are situated in the boundary-zone. The 

 arterial branches in this location form the 

 "arterial arcade." From this arcade per- 

 pendicular branches, the " interlobular arte- 

 ries," pass toward the capsule, taking a 

 straight course through the labyrinth be- 

 tween the medullary rays. In this course 

 they give off branches, the "afferent ves- 

 sels," which go to the Malpighian bodies. 



FIG. 133. 



FIG. 132. Diagram showing the course of the bloodvessels within the kidney. (Ludwlg.) a, 

 interlobular artery ; 6, interlobular vein ; c, Malpighian body, with the afferent vessel 

 entering it from the interlobular artery, and the efferent vessel leaving it to take part in 

 the formation of the capillary plexus between the renal tubules; rf, vena stellata; e, 

 arterisc rectse ; /, venae rectse ; g, capillary plexus around the mouths of the excretory 

 ducts. 



FIG. 133. Injected glomerulus from the horse. (Kolliker, after Bowman.) a, interlobular 

 artery ; of, afferent vessel ; m, m, capillary loops forming the glomerulus ; tf, efferent 

 vessel ; b, capillary network in the labyrinth and medullary rays. 



The main artery becomes smaller in giving off these branches, and 

 finally ends in terminal afferent vessels (Fig. 132). 



