424 



PHYSIOLOGY 



CHAT. 



VI 



of an artery into smaller branches, which end in a dense capillary 

 network, and ramify over the walls of the urinif'erous tubules,- 



their meshes being polygonal in the 

 cortex, and elongated in the medulla. 



While the blood which supplies the 

 cortex of the kidney traverses the inter- 

 lobular arteries to the glomeruli, and is 

 thence conveyed by the capillary net- 

 work of the interlobular veins (as well 

 as the venae stellatae), the blood supply 

 for the medulla passes through the 

 arteriae rectae, which are given off from 

 the arterial arches close to the inter- 

 lobular arteries, and then descend to- 

 wards the hilum, divide into minute 

 branches which form brushes or bundles, 

 and end in the long-meshed capillary 

 network of the medulla, after which 

 they are collected into the venae rectae 

 which are intermixed with the arteries 

 of the same name. There is thus a 

 comparative independence between the 

 cortical and the medullary circulation, 

 although they unite in a common net- 

 work of capillaries. 



Ve 



FIG. 115. (Let'r.) Diagram of distribution of blood-vessels in human kidney. (Ludwig.) ui,ni, 

 interlobular arteries ; vi, vi, interlobular veins ; g, glomerulus ; vs. stellate vein ; in; <v, arteriae 

 et venae rectae forming pencil-like bundles, ab, rb ; TJJ, venous plexus in the papillae. 



FIG. 116. (Right.) Malpighian glomenilus of injected human kidney. (Szymonowicz.) Va, 

 afferent vessel enormously enlarged by passive dilatation owing to pressure of injected fluid ; 

 Ve, efferent vessel, which is always much smaller than the afferent, but the difference in this 

 case is much exaggerated ; 1, 2, 3, U, vascular lobules of glomerulus. 



The uriniferous tubules and blood-vessels of the kidney are 

 united by interstitial connective tissue, which is more abundant in 



