346 



THE ANATOMY OP THE HORSE. 



dilatation — BowmaiCs capsule. Boioman's capsule surrounds a clue-like 

 tuft of capillary vessels called the glomerulus, and the whole constitutes 

 a malpighian body. It is more natural, but less simple at iirst, to 



regard the tube as beginning, 

 not at the crest of the pelvis, 

 but at Bowman's capsule. The 

 student should mentally work 

 it out in that direction for him- 

 self. The uriniferous tubules 

 consist of a basement mem- 

 brane with an epithelial lining. 

 In the convoluted and inter- 

 mediary tubes the cells are 

 irregularly columnar, but their 

 outlines are obscure ; in the 

 descending limb of Henle's 

 tube (nearest the capsule of 

 Bowman) the cells are 

 flattened ; and elsewhere the 

 cells lining the tubes are 

 cubical or columnar. 



The Kenal Vessels. The 

 renal artery divides into a 

 number of branches which 

 penetrate the kidney near the 

 hilus. Arriving between the 

 cortex and the boundary layer, 

 the arteries divide and anasto- 

 mose to form a series of arches 

 from which both cortical and 

 medallary vessels arrive. 



The cortical or interlobular 

 arteries are larger and more 

 numerous than those for the medulla. They pass directly outwards 

 towards the surface of the kidney, giving off lateral branches — the vasa 

 afferentia — to Bowman's capsule, and terminal branches to the fibrous 

 coat of the kidney. Each vas afferens pierces Bowman's capsule, and 

 resolves itself into the glomerulus, or capillary tuft. From this again the 

 blood is led out of Bowman's capsule by the vas efferens. The vasa 

 efferentia again resolve themselves into capillaries, and these form a 

 network among the convoluted tubes. From this intertubular capillary 

 network, small veins arise and pass to join the interlobular veins, running 

 alongside the arteries. These interlobular veins begin at the surface of 

 the kidney by the convergence of a number of minute veins from the 



Fig. 49. 

 Vessels of the Kidneys, and Uriniferous Tubules 

 (modified from Tamer). 

 1. Papillary duct ; 2. Collecticg: tube ; 3. Inter- 

 mediary tube ; 4. Looped tube of Henle ; 5. Con- 

 voluted tube ; 6. Bowman's capsule ; A. Segment of 

 artery forming renal arch ; B. Interlobular artery ; 

 C. Afferent vessel of glomerulus ; D. Efferent vessel 

 of the same ; E. Glomerulus ; P. Plexus formed by 

 vasa efferentia ; G. Arteriolffi rectaj ; H. Interlobular 

 vein. 



