The Skin and the Kidneys 201 



THE KIDNEYS 



v 307. General Structure of the Kidneys. The kidneys are 



of a reddish-brown color and lie between the upper lumbar 

 vertebrae and the crest of the hip bone, close against the 

 rear wall of the abdomen, with the intestines in front of 

 them. The human kidneys, though somewhat larger, are 

 of the same shape, color, and general appearance as those 

 of the sheep, so commonly seen in the markets. 



The hollow or concave side of the kidneys is turned 

 inwards, and the deep fissure of this side, known as the 

 hilus, widens out to form the pelvis of the kidney. Through 

 the hilus the renal artery passes into each kidney, and from 

 each hilus passes outwards the renal vein, a branch of the 

 inferior vena cava. 



A tube, called the ureter, passes out from the concave 

 border of each kidney, turns downwards, and enters the 

 bladder in the basin of the pelvis. This tube conveys the 

 secretion of the kidneys to the bladder. 



Experiment 91. Obtain a sheep's kidney in good order. Observe 

 that its shape is something like that of a bean, and note that the con- 

 cave part (hilus), when in its normal position, is turned towards the 

 backbone. Notice that all the vessels leave and enter the kidneys at 

 the hilus. Observe a small, thick-walled vessel with open mouth, from 

 which mg,y be pressed a few drops of blood. This is the renal artery. 

 Pass a bristle down it. With the forceps, or even with a penknife, 

 lift from the kidney the fine membrane enclosing it. This is the 

 kidney capsule. 



Divide the kidney in halves by a section from its outer to near its 

 inner border. Do not cut directly through the hilus. Note on the 

 cut surfaces, on the outer side, the darker cortical portion, and on 

 the inner side the smooth, pale, medullary portion. Note also the 

 pyramids of Malpighi. 



