

THE EXCRETION OF URINE 



385 



described. From these, a new vessel, the vas efferens, arises and this in its turn 

 breaks up into a capillary network which embraces the kidney tubules. Those 

 vasa efferentia which belong to the deeper layers of the cortex push down into 



the outer layer of the medulla, and from here run 

 between the renal tubules and break up into tufts 

 of vessels, whence again proceed capillaries to the 

 tubules. 



From the capillaries of the renal cortex the 

 blood collects in venous trunks which run parallel 

 with the radial arteries to the outer layer of the 

 medulla, and like them form an anastomosing 

 network at the base of the pyramids. Into this 



FIG. 143. Schema represent- 

 ing the distribution of the 

 blood vessels of the kidney, 

 after Ludwig. Arteries red, 

 veins blue. 



FIG. 144. Schematic representations of the secreting 

 and conducting elements of the kidney, after Ludwig. 

 I, Bowman's capsule; II, first convoluted tubule; 

 III, IV, Henle's loop; V, second convoluted' tubule; 

 VI, collecting tubule; r, cortex; g, medulla; p, papilla. 



network empty the veins from the medullary substance, which, like the 

 arteries, run in the interstices between the renal tubules and converge forming 

 tufted groups. 



The glomerulus interpolated between the vas afferens and the vas efferens 

 has the following structure. The afferent arteriole breaks up into several 



