KIDNEYS. 425 



the organ subdivides into 4 or 5 vessels. It is from these vessels 

 that the suprarenal capsules and the ureter also receive their 

 blood-supply. When, as frequently happens, there is a second 

 artery, it is called the inferior renal artery. 



The branches of the renal artery pass toward the cortex 

 and end as proper renal arteries, arterice proprice renales, from 

 which are given off the interlobular arteries in the direction of the 

 cortical substance, and the arteriolce rector toward the medullary 

 pyramids. From the interlobular arteries are given off the afferent 



Nuclei of en- 

 dothelial 

 cells of blood 

 capillaries. 



Lumen of uri- 

 niferous tu- 

 bule. 



Striated bor- 

 der. 



FIG. 242. Section of proximal convoluted tubules from man ; X 580 (Bohm and 



Davidoff). 



vessels, which pierce the capsules and end in the Malpighian tufts. 

 From the capsules emerge the efferent vessels, which form a venous 

 plexus about the uriniferous tubes, and the blood ultimately 

 leaves the kidney by the renal vein. 



Nerve-supply of the Kidney. The nerves of the kidney, from 

 15 to 20 in number, have ganglia upon them, and are from the 

 renal plexus. This plexus is formed from the solar plexus, semi- 

 lunar ganglion, lesser and smallest splanchnic nerves. So far as 

 known, the nerves are distributed to the arterioles principally, 



