THE KIDNEYS. 



1133 



The Renal Blood-vessels. The kidney is plentifully supplied with blood by 

 the renal arterv. a large offset of the abdominal aorta. Previously to entering 



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FIG. 723. Tran - n of pyramidal substance of kidney of pig, the blood-vessels of which are injected, 



a. Large collecting tube cut across, lined with cylindrical epithelium, b. Branch of collecting tube cut across, 

 lined with epithelium with shorter cylinders, c and d. Henle's loops cut across, e. Blood-vessels cut across. 

 D. Connective-tissue ground-substance. 



the kidney, each arterv divides into four or five branches, which are distributed 

 to its substance. At the hilum these branches lie between the renal vein and 

 ureter, the vein being usually in front, the ureter behind. Each vessel gives 

 off some small branches to the suprarenal capsules, the ureter, and the sur- 



Fio. 724.-Diagrammatical sketch of kidney. 



FIG. 725. A portion of Fig. 593 enlarged. (The 

 references are the same.) 



A, o. Proper renal artery and vein, the former giving off the renal afferents, the latter receiving the renal 

 efferents. B, b. Interlobular arterv and vein, the latter commencing from the stellate veins, and receiving 

 branches from the plexus around the tubuli contorti.the former giving off renal afferents. c. Straight tube, sur- 

 rounded by tubuli contorti, with which it communicates, as more fully shown in Fig. 586. D. Margin of medul- 

 lary substance. E. E. E. Receiving tubes cut off. F,/. Arteriolae et venae rectse, the latter arising from (G) the 

 plexus at the medullary apex. 



rounding cellular tissue and muscles. Frequently there is a second renal artery, 

 which is given off from the abdominal aorta at a lower level, and supplies the 

 lower portion of the kidney. It is termed the inferior renal artery. The 

 branches of the renal artery whilst in the sinus give off a few twigs for the 

 nutrition of the surrounding tissues, and terminate in the arterice proprice renales, 

 which enter the kidney proper in the columns of Bertin. Two of these pass 

 to each pyramid of Malpighi and run along its sides for its entire length, 



