440 PHYSIOLOGY. 



nucleated, epithelial cells, these even dipping down between the 

 capillaries. 



From the center of the glomenilus there proceeds a vessel that 

 is somewhat smaller than the afferent vessel, known as the efferent 

 vessel; it is a vein, and leaves the capsule very close to the point 

 of entrance of the vas afferens. 



The efferent vessel also divides to form a secondary capillary 

 network, the renal portal system, with elongated meshes in the situa- 

 tion of the pyramids of Ferrein; from this plexus arise the inter- 

 lohular veins which run parallel to the interlobular arteries. 



The medulla of the kidney receives its arterial supply from the 

 arterice rectce; these latter are vessels which spring either from the 

 arterial arches or from the interlobular arteries. According to some 

 authors, they may be derived from the afferent vessels of the deepest 

 and largest glomeruli. Within the pyramids the arteria? rectse 

 divide and subdivide to form a plexus of capillaries which eventually 

 merge into the vence rectce., to empty into the venous trunks at the 

 boundary between the medulla and cortex. 



The renal veins arise from three sources : (1) the venous plexus 

 beneath the capsule, (2) the plexus around the tubuli contorti, and 

 (3) the plexus located near the apices of the pyramids. Within the 

 sinus the larger branches from these plexuses inosculate to form the 

 renal veins, which pass through the hilus to empty into the inferior 

 vena cava. 



The vasa recta circulation is of prime importance in that it 

 forms a sidestream through which much blood may pass without 

 being compelled to traverse the glomerulus. It is very apparent 

 that this circulation is highly useful in conditions of kidney conges- 

 tion as a sidestream. 



Three kinds of capillaries are found within the kidney: (1) 

 gkmerular, (2) efferent capillaries, and (3) capillaries of the vasce 

 rectce. The kidney, for its size, is abundantly supplied with blood. 



Lymphatics. The kidneys are richly supplied with lymphatics, 

 occurring as slits. The renal lymphatics terminate in the lumbar 

 lymphatic glands. 



Nerves. The nerves of the kidney accompany its blood-vessels, 

 ganglionic plexuses being numerous. They are from the renal 

 plexus, coming originally from the solar plexus. 



