386 



PRACTICAL ANATOMY. 



extremity rests the .supra-renal capsule. Each kidney is 

 imbedded in a quantity of firm fat. 



If a section is made of the kidney it is seen to con- 

 sist of two portions, an outer or cortical, and an inner 

 or medullary. The cortical matter consists of convoluted 

 tubuli, Malpighian corpuscles, and vessels. The medul- 

 lary portion consists of 

 from sixteen to twenty 

 conical masses of straight 

 tubuli, called the pyramids 

 of Malpighi. The cortical 

 substance makes one-third, 

 the. medullary two-thirds 

 of the section. The sinus 

 of the kidney is occupied 

 by the pelvis of the ureter, 

 which is the upper dis- 

 tended portion of the tube ; 

 it presents three funnel- 

 shaped depressions, called 

 the infundibula, the su- 

 perior, middle, and infe- 

 rior. The lining mucous 

 membrane is thrown into 

 ridges, which subdivide 

 the infundibula into twelve 

 to eighteen alveoli, called 

 the calyces. The apices 



of the Malpighian pyramids present at the bottom of the 

 calyces. 



A minute examination of the apex of the pyramid 

 reveals the open mouths of numerous tubuli, which should 

 be carefully followed, so as to understand the structure 

 of the kidney. The tubule proceeds in a straight direc- 



FIG. 167. LONGITUDINAL SECTION OF 

 A MALPIGHIAN PYRAMID. 



PF, pyramids of Ferrein ; RA, branch of renal 

 artery : RV, lumen of a renal vein receiving an in- 

 terlobular vein ; VK, vasa recta ; PA. apex of a renal 

 papilla ; b, b, embrace the bases of the renal lobules ; 

 h, cortex ; i. boundary or marginal zone ; k, papillary 

 zone. 



