THE ABDOMEN 



823 



one another. The convexities of the incomplete arterial arches 

 are directed towards the cortex, and the concavities towards the 



Malpighian p\Taniids. The 

 branches of the arches are inter- 

 lobular and arteriae rectae. 



The interlobular arteries (cor- 

 tical) arise from the convexities 

 of the arches and enter the laby- 

 rinth of the cortex, in which 

 they pass outwards between the 

 medullary rays. They give off 

 afferent and capsular branches. 



The afferent branches are so 

 named because they carry blood 

 to the glomeruli or Malpighian 

 corpuscles. They arise from the 

 interlobular arteries at frequent 

 intervals, and each passes to a 

 capsule of Bowman without 

 giving ofi any branch. Having 

 pierced the capsule at one pole, 

 the afferent vessel breaks up 

 into a number of convoluted 

 capillary vessels, which form a 

 small vascular ball, called a 

 glomerulus or Malpighian cor- 

 puscle. The blood is conveyed 

 away from the glomerulus b}' an 

 efferent vessel, which is variously 

 regarded as an artery and a vein. 

 This efferent vessel is smaller 

 than the afferent artery. Tt 

 pierces Bowman's capsule at the 

 same pole as the afferent artery, 

 but separate from, though close 

 to, it. Thereafter it breaks 

 up into a network of capillary 

 vessels, which invest the corre- 

 sponding proximal convoluted 

 uriniferous tubule, the meshes of the network being polygonal. 

 The efferent vessels of those glomeruli which lie nearest to the 

 Malpighian pyramids are disposed in a different manner. They 

 break up into bundles of straight vessels, called false vasa recta, 

 which enter the boundary zones or basal parts of the pyramids, 

 where they supply to a large extent the uriniferous tubules, upon 

 the walls of which they form capillary networks with elongated 

 meshes. It is, however, to be noted that the Malpighian pyramids 

 also receive true arteriae rectae from the cortico-medullary arterial 

 arches. 



Fig. 



355. — Diagram of the Blood- 

 vessels OF THE Kidney. 



A, Cortex ; B, Medulla, 



1. Arterial Arch 



2. Interlobular Artery 



3. Afferent Artery of Glomerulus 



4. Capsular Branches 



5. Efferent Vessel of Glomerulus 



6. Malpighian Corpuscle 



7. Proximal Convoluted Tubule 



8. True Arteria Recta 

 q. False Arteria Recta 



10. Venous Arch 

 It. Interlobular Vein 



12. Venae Stellatse 



13. Venae Rectse 



