EXCRETION 



LXI. STUDY OF *A LAMB'S KIDNEY (OPTIONAL). 



Apparatus. A fresh lamb's kidney with its capsule of fat, scalpel. 



Directions. Carefully remove the outer layer of fat and 

 the membranous inner capsule. What is the function of this 

 material? (A dissection of the rat makes a good demon- 

 stration of the location of the 

 kidneys and their relation to 

 ureter and bladder.) Cut the 

 kidney lengthwise so as to split 

 the ureter where it emerges from 

 the concave side. On the cut 

 surface make out the pale inner 

 striated medulla and its pyramids 

 of Malpighi, the outer cortex , and 

 the intermediate layer between the 

 two. Note also the enlarged upper 

 end, or pelvis , of the ureter; the 



Cavity, Or sinUSj into Which it FIG. 44. Diagram of a Longitu- 



opens; and the tubes, or calices, dina ! Se f on of a ney: a ' 



renal artery; c, capillaries; g, 

 between the projecting pyra- glomerulus; t, uriniferous tubule; 



mids. Note also the entrance of 



the renal artery into the kidney, and the renal vein, just 

 above the ureter. From the accompanying Fig. 44 make 



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