CHAPTER XV 

 ELIMINATION. ORGANS OF ELIMINATION. 



THE KIDNEYS 



Having studied the Digestive, Circulatory and Respiratory 

 Organs, or organs of nutrition, we will next consider those which are 

 active in the removal of waste from the system or the Organs of 

 Elimination. They are the kidneys, skin, liver and lungs, and to a 

 lesser extent, the intestinal canal. 



Of these, the kidneys alone are specially constructed for the 

 function of elimination only. The skin, although mainly an organ 

 of excretion (or elimination), has other uses beside (as will be seen 

 in succeeding pages). 



The liver and the lungs are included under this heading the 

 liver, because certain waste products are contained in the bile; 

 the lungs, because they are agents for the removal of carbon dioxide. 

 The intestinal tract is the avenue by which the gross waste material 

 of the food is expelled, and at the same time it is the main avenue of 

 entrance into the system of nutritive material. Therefore the 

 lungs, liver, and intestine are found in both lists of organs, nutritive 

 and eliminative. 



THE KIDNEYS 



The kidneys (renes) are the most important organs of excretion. 

 They separate certain waste matters from the blood, in a definite 

 form for removal from the body; this is their special function. 



They are situated for the most part in the posterior lumbar 

 region, just in front of the quadratus lumborum muscles, extending 

 from about the tenth rib to within two or three inches from the 

 crest of the ilium. They are shaped like a bean, about four or 

 five inches long and one and one-half inches wide, with the concave 

 border, or hilus, turned toward the spinal column; and they are 

 imbedded in fat behind the peritoneum. This is the fatty capsule; 

 outside of it a thin layer of fascia extends across both kidneys, 

 being attached to the fascia in front of the lumbar muscles and 

 lumbar spine. It is called the renal fascia. 



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