1884 



Blood-Vessels - /;/,,/,,. -The renal arteries-usually one to each kidney 

 hut SStSf 3 S exceptional cases three or even our are of unequal 





or less maked by tin- renal veins, to the hilum of the kidney dunng their 

 eivinu off small twiga to tin- capsula adiposa as well as to the suprarenal bod 

 1 us U,, v u,rinu 7h,. kidney, or within tin- hihim, the renal artery divides into an 

 -- t i > ventral: and a posterior I dorsal , branch, each of which embraces -the pel- 

 divide, im,, four', , nxv twigs that hu, their respective wal o the -ui. 

 o entering the kidney, each twig 



FIG. 



1611. 



T\v<> ralyces 



renal substance through the vascu- 

 lar foramina surrounding the pa- 

 pilla;. On entering, they pass 

 along the sides of the papilla-, their 

 course corresponding in position to 

 the original tracts of connective tis- 

 sue that separate the primary di- 

 visions of the foetal kidney (page 

 1876) ; they are therefore appro- 

 priately designated intcrhbar ar- 

 teries. The general expansion of 

 the branches derived from the an- 

 terior and posterior arteries is par- 

 allel to the corresponding ventral 

 and dorsal surfaces of the kidney ; 

 the intervening zone along the 

 convex border of the organ, about 

 i cm. on the posterior surface, 

 contains few, if any, of the larger 

 vessels and, in consequence, ap- 

 pears lighter in color. The vessels 

 supplying the kidney do not anas- 

 tomose, each such "end" artery 

 providing for a particular area of 

 renal substance. On reaching the 

 level of the bases of the renal 

 pyramids, each interlobar artery 

 breaks up into a tree-like bundle 

 of twigs, some of which pursue an 

 arched course across the bases of 

 the pyramids, thereby producing 

 the impression of a series of arcades 

 .it the junction of the medulla and cortex. From these vessels two series of terminal 

 branches arise, one for the supply of the cortex, the other for that of the medulla. 



Tin- itnliiti/ tirtcriolt-s pursue a course ^em-rally perpendicular to the free surface, towards 

 which they run Ix-tween the cortical lobules, -ivin^ off short lateral twi^s that end as tin- \asa 

 uti.i in the ^lomeruli of the Malpi^hiau bodies. The latter are arranged in columns in 

 correspondence with the path of the interlobular cortical arterioles. Some of these, however, 

 do 11 . atTereiitia. but ascend to the kidney capsule, for the supply of which they 



provide in conjunction uith the direct branches from the renal artery. 



li.uerxiu^ the capillary complex, the blood is carried from the -lomerulns by the 



ii,. \\liiih. smaller than the v.is .itf.-rens, on its exit immediately breaks up into the 



,;/<,;/>///</; i,^ that form uet-u< >rks enclosing the tubules within the labyrinth, and, continuing, 



surround those within the medullary ra\ . in the latter situation the meshes bein- relatively longer 



and mote open and i mitainini; blood that has al reach supplied the proper nriniferous tubules. 



Tin- >n'\/ii//.it-y ,iit,ti"/,-^ derived in part from the terminal branches of the interlobar 

 stems at the b.ises of the- pyramids, descend within the latter as bundles of radially disposed 



Inferior division of pelvis 





^""f'"" pn-par.ition of injected right kidney. 

 vK\n<l it. mi behind, bowing relations o( branches of 



K-nal :irtriv t 'li\ i-.ii.iis i it rt-nal |><-l\ is 



