ANATOMY, EMBRYOLOGY AND HISTOLOGY 



65 



The Paraganglia. It is interesting to note that sympathochromaffin 

 tissue also develops into other organs in addition to the suprarenal glands. 

 It gives rise to the so-called chromaphil bodies, which are also referred 

 to as paraganglia, owing to their topographical relationship to the sympa- 

 thetic ganglia. They are thought to vary in number from five to twenty- 

 five or even thirty. The largest are the aortic bodies, about one centi- 

 meter long, situated in the vi- 

 cinity of the abdominal aorta 

 between the kidneys (Fig. 3). 

 All of them, with the possible 

 exception of the carotid body, at- 

 tain their maximum development 

 before birth and later undergo 

 retrogressive changes. In adults 

 they can rarely be detected with- 

 out microscopic examination. 

 Biedl and Wiesel have shown that 

 extracts of these bodies have the 

 same physiological action as ex- 

 tracts made from the medulla of 

 the gland, which observation is 

 confirmed by the more recent 

 work of Fulk and Macleod. 



Variations in the Suprarenals 

 under Different Conditions. 

 With Sex Anomalies. Excessive 

 development or hyperplasia of 

 the cortex of the suprarenal 

 glands has been found by Glynn 

 and others to be associated with 

 the development of secondary 

 male characters, such as hairi- 

 ness, in females. This relationship is discussed at length in the section 

 on clinical suprarenal syndromes. 



Seasonal Variations. Observations on seasonal variations in the 



Fig. 3. Aortic bodies of newborn baby 

 from Piersol, after Zuckerkandl. 



weight of the suprarenal glands are on record. Stilling, for instance, 

 found an increase in size in male rabbits during the breeding season ; and, 

 according to Glynn, Aichel has confirmed J^agel's observation of 'similar 

 changes in amphibians and birds, Glynn is of the opinion that much the 

 same alterations take place in human beings, but statistics are entirely 

 wanting. 



Sex Differences. Hatai and Jackson are agreed that in the white rat 

 there is a distinct sexual difference in the suprarenals(fr), that they are 

 relatively much larger in the female, especially during pregnancy and lac- 



