268 NORMAL, HISTOLOGY AND ORGANOGRAPHY. 



the vas afferens and the smaller vein the vas efferens. 

 The latter, instead of uniting with other veins to form 

 larger trunks, as is the case in other organs, passes 

 directly to the convoluted tubules, where it forms 

 a dense capillary system that ramifies everywhere 

 over the walls of these tubules. Many of the effer- 

 ent vessels from the lowermost glomeruli, that is, 

 those nearest the medulla,, break up into pencils of 

 straight vessels called pseudo-arteries recta, which 

 pass directly into the medulla to form capillaries 

 around the tubules of this part. 



Interlobular 'veins convey the blood from the kid- 

 ney cortex to the venous arches at the base of the 

 pyramids. Near the periphery of the kidney other 

 veins converge to form a stellate appearance just 

 beneath the capsule. These stellate veins receive 

 blood from the venous arches and also connect with 

 the veins of the capsule. 



The blood supply of the medulla is to a great ex- 

 tent independent of that to the cortex, excepting that 

 supplied by the-false arteriae rectae. Branches from 

 the concave side of the arterial arches pass directly 

 into the medulla, where they form bunches of pencils 

 of small parallel vessels, the arteries recta, which sup- 

 ply blood to the walls of the uriniferous tubules of 

 this part. Veins return this blood to the venous 

 arches that lie between the cortex and medulla. 

 These arches form veins that pass through the col- 

 umns of Bertini and ultimately drain into the renal 

 vein, which passes through the hilum to join the 

 inferior vena cava. 



On account of this extensive blood supply any 

 renal disturbance is, as a rule, accompanied by a cor 



