1460 



HANDBOOK OF PHYSIOLOGY 



CIRCULATION II 



CORTEX 



fig. 4. The medullary and papillary blood supply of the 

 kidney. [After Baker (6).] 



are common in the dog kidney between interlobar 

 veins, between arcuate veins, and between stellate and 

 arcuate veins (322). 



arteriovenous anastomoses. The venous sinusoids 

 have been described as the site of numerous arterio- 



venous anastomoses in the human kidney by Spanner. 

 Barriet et at. (12) believe that such arteriovenous 

 connections occur between the aforementioned 

 spiral arteries and the sinusoids, the latter emptying 

 presumably into the interlobar veins, but admit that 

 open communications between the spiral arteries and 

 the sinusoids are extremely difficult to demonstrate. 

 Trueta et at. have disputed Spanner's findings, and 

 Baker (6) found only an insignificant number in 

 confirmation of Trueta. Nor could von Kiigelen 

 et at. (322, 323) and Christensen (54) find them in 

 the dog kidney. 



In summary, arterio-arterial and veno-venous 

 anastomoses occur commonly in the kidneys of man 

 and dog. Although arteriovenous anastomoses prob- 

 ably exist, their occurrence is infrequent. Func- 

 tionally, direct A-V shunting of blood must therefore 

 be negligible, and blood passes generally through a 

 capillarv circuit (cortical peritubular plexus or 

 medullary vasa recta system). In confirmation, 

 Piiper & Schiirmeyer (249) found that the intact 

 dog kidney passed only 1.5 per cent of 19 n wax 

 spheres injected into the renal artery, 0.3 per cent 

 of 30 n, and 0.08 per cent of 38 ^ size. Denervation, 

 and injection of KCN, novacaine, and histamine did 

 not influence the results. Although Simkin et at. 

 (283) recovered glass spheres up to 440 m in size from 

 the renal vein of excised human kidneys, they did not 

 indicate what portion these represented of the total 

 injected. 



venous valves and valvelike structures. These 

 have been described by von Kugelgen et at. (320-322) 

 in the dog, swine, and human kidney. They are 



V.s fellah. 



fig. 5. The blood supply of the cortex, in- 

 cluding the venous system, a/: Arterial-free 

 zone of the cortex; vf: vein-free zone of the 

 cortex. [After von Kugelgen et at. (322).] 



V. corti calis 

 superficial/! 



/cortical is 

 profunda 

 V. interlobularis 



V.interlobans 



