58 



Kidneys. 



supra- 

 renalis 



395. Tlie liiglit Kidney and Supra-renal Capsule. 



*/ 3 natural size. 



The kidneys, llcnes, are situated in the lumbar region at the back 

 part of the abdomen ; they have somewhat the shape of a bean ; their anterior 

 surfaces are covered by peritoneum, their posterior lie on the Musculi gua- 

 drato-lumborum. The right kidney, placed somewhat lower than the left, is in 

 relation anteriorly with the ascending colon, the left with the descending 

 colon. The internal, concave border presents a fissure, the Hilus s. Porta rents, 

 for the entrance and exit of the renal vessels. They are surrounded by loose 

 areolar tissue containing much fat, Capsula adlposa, and by a proper fibrous 

 coat, Capsula jibrosa, which forms a thin, smooth investment, closely 

 covering the organ. The surface of the kidney is in the adult entirely 

 smooth, but in the new-born is divided into lobules, ficncs lobati (see 

 Fig. 394). On splitting open the kidney by a longitudinal section, it is 

 found to consist of a medullary substance, Substantia medullaris s. tubulosa, 

 around which is the reddish-brown cortical substance, Substantia corticalis 

 x. vasculosa s. ylomcrulosa ; the former consists of palish-red masses, the 

 pyramids of Malpighi, 10 15 in number, whose apices, directed towards 

 the hilus, are called Papillae rcnales. The prolongations of the cortical sub- 

 stance between any two pyramids are called columns of Bertini. 



