GENERAL ZOOLOGY 



Neurosecretory 

 cells in brain 



Neurosecretory 

 material stored in 

 corpus cardiacum 



Material depleted 

 on operated side 



Normal corpus 

 allatum 



Corpus allatum 



larger on 



operated side 



Fig. 17.8. Neurosecretory function in an insect, Leiicophaea maderae. The material produced 

 in the cerebral neurosecretory cells normally flows posteriorly through nervous connections into 

 a storage organ, the corpus cardiacum, and exerts an effect on a pair of endocrine organs, the 

 corpora allata. If the nervous connection between brain and corpus cardiacum is se\ered, 

 neurosecretory products accumulate at the point of section, the material stored in the corpus 

 cardiacum is depleted, and changes occur in the function of the corpus allatum. (Adapted 

 from B. Scharrer, 1952, Biological Bullelm, vol. 102, printed b\' permission.) 



In the best-known examples, among arthropods, difTerent groups of neuro- 

 secretory cells form functional endocrine systems. Some environmental or 

 physiological change causes the release of a hormone by one gland, and this 

 hormone has the specific effect of stimulating another gland to produce its 

 secretion, which in turn e.xerts its systemic or specific effect. In many 

 invertebrates the relationships are complex, just as they are in mammalian 

 endocrine systems (pp. 117 124). It is well known that among mammals 

 the hormones are generallv not "species specific" in their action; hormones 

 used for the treatment of human endocrine insufficiencies are obtained 



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