THE TJRO-GENITAL SYSTEM 



171 



lobules. The renal artery (Fig. 53, No. 5,, 3) breaking up into 

 arterioles in the. kidney, and finally reaching the cortical portion 

 of the lobules, form capillary plexuses in the shape of minute spheres, 

 which are the glomerules (Fig. 53, No. C, 3 and B, 5). Around each 

 glomerule there is formed a capsule called Boisrman's capsule, which 

 is the beginning of the uriniferous tubule. This entire mass is called 

 the Malpighian body, or renal corpuscle. This capsule then ex- 

 tends as the urinary, or secreting tubule, being at first constricted, 

 then convoluted, and terminates into a second portion, the descend- 



FiG. 51. — The kidneys. 10, The posterior, ib, the middle and ic, the anterior 

 lobes of the kidney. 2, The posterior aorta. 3, The external iliac or crural 

 artery. 4, The ischiadic artery. 5, The sacralis media artery. 6, The ureter 

 which empties into the cloaca at 7. 8, The external iliac vein. 9, The internal 

 iliac vein. 10, The iliacus communis. 



ing limb of Henle. This portion of the tubule becomes constricted. 

 It then forms the loop of Henle and ascends as: the second portion, 

 or second Hmb of Henle, which is again of greater diameter. The top 

 of the secreting tubule is sUghtly wavy and empties into the col- 

 lecting tubule along with many others. These collecting tubules 

 in turn merge into large tubules which finally empty into the ureter 

 (Fig. 53, No. 14). These collective bundles correspond to the pyra- 

 mids of the kidneys of mammals. 



