BLOODVESSELS OF THE KIDNEY. 



99 



The exact relations of this investment are still very obscure. 

 It is apparently stretched uniformly over each lobule of which 



Fig. 150. 



VI. 



Fig. 150. Diagram of the circulation in the 

 kidney, a i, Arteria interlobularis, sending 

 numerous vasa afferentia to the glomeruli (g) ; 

 the vas efferens proceeding from each of the 

 latter run in the cortex, partly into the 

 wide-meshed capillary network of the medul- 

 lary rays, partly into the narrow-meshed 

 plexus of the tortuous canals. From these 

 plexuses the venae stellatse (v s) are formed 

 at the surface of the cortex, and the venae 

 interlobulares (v i) in the labyrinth of the 

 cortex. Into the medullary portion penetrate 

 the arteriae rectae verae (a r), proceeding from 

 the renal arteries, and also the vasa efferentia 

 of those glomeruli which are situated around 

 the medulla. From the arterial fasciculus 

 (a 6), formed by the arteriae rectae, the 

 capillaries destined for the urinary tubuli of 

 the medulla take their origin. The blood 

 circulating in these plexuses is returned by 

 the venulae rectae, of which many run 

 together to form a fasciculus with parallel 

 striation, as at v b. The vessels of this 

 fasciculus coalesce to form a venous trunk 

 (v r), which empties itself into a large renal 

 vein. A venous plexus (vp) surrounds the 

 openings of the urinary tubules upon the 

 papilla. 



the glomerulus is composed, and consequently binds the several 

 vessels together ; on the other hand, it is not extended from 



H 2 



