COORDINATION AND CONTROL: (2) THE ENDOCRINE GLANDS 133 



bile into the intestine; another increases the production of pancreatic enzymes 

 without increasing the amount of pancreatic juice; a third inhibits gastric secre- 

 tion; and the fourth excites secretion in the intestinal glands. 



Gonads. The soma cells of the testis and ovary produce hormones that regu- 

 late various sexual phenomena and body characteristics. Since their primary roles 

 are concerned with reproduction, they will be discussed in the chapter dealing 

 with reproduction in man. 



We have now dealt at least briefly with all aspects of the human body 

 that are related to its successful existence as an individual organism. We 

 are nearly through with man, considered solely as an illustration of how 

 the individual animal is built and how it works. There remains, however, 

 one important feature of the human body — the reproductive system— 

 which has scarcely been mentioned. The reason it has not yet been men- 

 tioned is that this system is not essential for the existence of the individual 

 but has to do with the perpetuation of the race to which the individual 

 belongs. It will be discussed in the following section of the book, which is 

 concerned with our second viewpoint, the continuity of the race. Never- 

 theless the reproductive system is not segregated from the remainder of 

 the body; it has important influences upon the individual considered as 

 an individual. Therefore our survey of the structure and function of the 

 individual human organism cannot be considered complete until the 

 topic of reproduction has been covered. 



