CHAPTER 12 

 THE ENDOCRINAL ORGANS 



One necessity of a living organism is that its organs should work 

 together. In fact, a difference between a living creature and a dead one 

 is that the Uving organism is integrated and the dead is not. More- 

 over, the more complex an organism, the more difficult it is to secure 

 functional correlation among its different but interdependent parts, and 

 the more complicated is the mechanism which accomplishes this end. 



-PITUITARY 



-PARATHYROIDS 



DUODENUM—/ 



PANCREATIC 

 ^ A" I SUANDS 



Fu,. 288. — The endocrinal glands in man. 



This functional integration of the animal body is brought about by 

 two means, one nervous, the other chemical. In general, quick adjust- 

 ments, muscular activities and correlations, and responses to the outward 

 environment are controlled by the nervous system. But growth, for 

 example, and metabolism and, in general, the adjustment of the several 

 tissues to one another, is largely taken care of by the ductless or endocrine 

 glands, which secrete into the blood stream minute quantities of so-called 



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