1134 



THE URINARY ORGANS. 



giving off as they advance the afferent vessels of the Malpighian bodies in 

 the columns. Having arrived at the bases of the pyramids, they make a bend 

 in their course, so as to lie between the bases of the pyramids and the cortical 

 arches, where they break up into two distinct sets of branches devoted to the 

 supply of the remaining portions of the kidney. 



The first set, the interlobular arteries (Figs. 724, 725 B), are given off at right 



angles from the side of the arterige propriae re- 

 nales looking toward the cortical substance, and, 

 passing directly outward between the pyramids 

 of Ferrein, they reach the capsule, where they 

 terminate in the capillary network of this part. 

 In their outward course they give off lateral 

 branches ; these are the afferent vessels for the 

 Malpighian bodies (see page 1130), and, having 

 pierced the capsule, end in the Malpighian tufts. 

 From each tuft the corresponding renal efferent 

 arises, and, having made its egress from the 

 capsule near to the point where the afferent ves- 

 sel entered, anastomoses with other efferents 

 from other tufts, and contributes to form a 

 dense venous plexus around the adjacent urin- 

 ary tubes (Fig. 726). 



The second set of branches from the arterige 

 propiae renales are for the supply of the medul- 

 lary pyramids, which they enter at their bases ; 

 and, passing straight through their substance 

 to their apices, terminate in the venous plex- 

 They are called the arteriolce rectce (Figs. 724, 



FIG. 726. Diagrammatic representation 

 of the blood-vessels in the substance of the 

 cortex of the kidney, m. Region of the 

 medullary ray. b. Region of the tortuous 

 portion of the tubules, ai. Arteria inter- 

 lobularis. vi. Vena interlobularis. va. Vas 

 afferens. gl. Glomerulus. ve. Vas efferens. 

 vz. Venous twig of the interlobularis. (From 

 Ludwig, in Strieker's Handbook.) 



uses found in that situation. 

 725 F). 



The Renal Veins arise from three sources the veins beneath the capsule, the 

 plexuses around the tubuli contorti in the cortical arches, and the plexuses situated 

 at the apices of the pyramids of Malpighi. The veins beneath the capsule are 

 stellate in arrangement, and are derived from the capillary network of the capsule, 

 into which the terminal branches of the interlobular arteries break up. These 

 join to form the vence interlobular 'es, which pass inward between the pyramids of 

 Ferrein, receive branches from the plexuses around the tubuli contorti, and, 

 having arrived at the bases of the Malpighian pyramids, join with the venae rectge, 

 next to be described (Figs. 724, 725 ft). 



The Vence Rectce are branches from the plexuses at the apices of the medullary 

 pyramids, formed by the terminations of the arteriolae rectae. They pass outward 

 in a straight course between the tubes of the medullary structure, and joining, as 

 above stated, the venae interlobulares, form the proper renal veins (Figs. 724, 725/). 



These vessels, Vence Proprice Renales, accompany the arteries of the same name, 

 running along the entire length of the sides of the pyramids ; and, having received 

 in their course the efferent vessels from the Malpighian bodies in the cortical 

 structure adjacent, quit the kidney substance to enter the sinus. In this cavity 

 they inosculate with the corresponding veins from the other pyramids to form the 

 renal vein, which emerges from the kidney at the hilum and opens into the inferior 

 vena cava, the left being longer than the right, from having to cross in front of 

 the abdominal aorta. 



Nerves of the Kidney. The nerves of the kidney, although small, are about 

 fifteen in number. They have small ganglia developed upon them, and are derived 

 from the renal plexus, which is formed by branches from the solar plexus, the 

 lower and outer part of the semilunar ganglion and aortic plexus, and from the 

 lesser and smallest splanchnic nerves. They communicate with the spermatic 

 plexus, a circumstance which may explain the occurrence of pain in the testicle in 

 affections of the kidney. So far as they have been traced, they seem to accompany 



