Tin: ENDOCRINE ORGANS, OB DUCTLESS GLANDE 



and by observing the pathological changes in tin- various endocrine orgj 

 In diseased conditions. Embryological and histological studies are i 

 the greatest importance. A difficulty in investigatit *ion of 



an endocrine organ lies in the fad that the secretion of no one gland 

 acts independently of those from other glands. < »n the contrary, there is 

 undoubtedly a close association of function, v., that we can not tell 

 whether a change of function observed after removal of some gland 

 administration of some extract is a direct consequence of the experi- 

 mental procedure, or is induce. 1 by some secondary - eloped on 

 another endocrine organ. It will no doubt take many years hefore suf- 

 ficient data have been collected to enable us definitely tate what the 

 particular function of each endocrine organ may be. Since most pi 

 has been made in connection with the adrenal gland, it will be advan- 

 tageous to consider the functions of this gland first. 



ADRENAL GLAND 



In mammals the adrenal gland is composed of two parts, th< x and 



the medulla. In other groups of animals however, these two are more or 



3 separate, being completely so in fishes. This not infrequent separa- 

 tion of cortex and medulla suggests a different function for the I 

 structures. Experimental investigation supports this view. 



The Cortex 



The cortex on microscopic examination is Been to be composed of rows 

 of epithelial cells arranged more or less in columns except at the 

 periphery, where they form glomerular mass< 3, and next the medulla, 

 where they assume a reticular formation. The cells of the greater part 

 of the cortex, unlike those of the medulla, contain no granules with 

 special Btaining qualities, but they do contain particles which are be- 

 lieved t<> be composed of cholesterol esters and lecithin. In the cells 

 the reticular portion of the cortex, however, pigment part re not 



infrequently observed. The blood supply of the cortex is not relative]-, a 

 rich as that of the medulla, being represented by fine arterioles which 

 run inwards from the capsule towards the medulla in the connective ' - 



Nile that lies between tli Jumna of cortical cells. N es similarly 



penetrate into the cortex, some supplying its blood, vessels and cell 



columns, but most mi* them pro ling to the medulla. Th<\\ are der 



from ,i network of nerve fibers in the capsule of the organ, and the ni 

 supply of this network comes partly from the suprarenal plexus, and 

 partly from the splanchnic nerve. Embryologically ihe cortex is 

 veloped from the cells of the genital ridge, thai is, from mesodermic 



cells. 



