THE URINARY ORGANS. 



193 



FIG. 236. 



parenchyma of the organ is held in place by the interstitial con- 

 nective tissue ; this is present between the tubules in most parts of 

 the kidney in very small quantities, the immediate vicinity of the 

 Malpighian bodies and the papillary region of the medulla being 

 exceptions, since considerable amounts of the interstitial tissue are 

 present in these localities. The connective tissue of the kidney be- 

 comes condensed at the periphery of the organ, where it forms a 

 fibrous investment, over which, in addition, the special capsule 

 extends. 



The Malpighian bodies are situated exclusively within the cortex, 

 and are limited to the labyrinth. 'They consist of two parts a 

 spherical mass of convo- 

 luted capillary blood-ves- 

 sels, the glomerulus, or 

 the Malpighian tuft, and 

 the surrounding expanded 

 extremity of the uriniferous 

 tubule, the capsule of 

 Bowman. The glomer- 

 ulus is supplied by an 

 afferent artery, which 

 divides into several 

 branches ; each of these 

 breaks up into numerous 

 capillaries, which are 

 united by delicate con- 

 nective tissue into groups 

 or lobules. The blood 

 escapes from the convo- 

 luted capillaries of the 

 glomerulus by the effer- 

 ent vessel, which passes 



Section of human kidney partially injected : a, interlobu- 

 lar artery giving off afferent twig (6) ; c, efferent vessel 

 passing into intertubular capillaries (</) ; e, convoluted 

 capillaries of glomerulus ; f, outer layer of Bowman's cap- 

 sule, the nuclei of whose cells show at g ; h, uriniferous 

 tubule in transverse section, , in oblique section. 



out by .the side of the en- 

 tering artery. 



The glomerulus, as 

 usually seen in sections, 

 seems to lie within the 

 capsule, the blood-vessels having apparently pierced the latter to 

 gain entrance. The vessels, however, really are outside the cavity 

 of the capsule, since one surface of this structure has been pushed in 

 before the advancing tuft during its development. The masses of 

 convoluted capillaries are closely invested by the reflected portion 

 of the capsule, which likewise dips in between the vascular lobules 

 of the glomerulus. The invaginated portion becomes continuous 



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