THE PITUITARY BODY 



THE INNERVATION OF THE PITUITARY BODY 



It has been known for many years that the pars glandularis 

 receives sympathetic nerve fibers from the carotid plexus. In 

 the cat these non-myelinated fibers accompany the arteries 

 and terminate chiefly in the pars glandularis and the pars 

 neuralis. Not all the nerve fibers degenerate after cervical 

 sympathectomy, and some may be parasympathetic in origin 

 (Hair, 1938). The functional significance of this innervation, 

 however, has not yet been adequately explored. Evidence of 

 a nervous regulation of the pars glandularis is slowly ac- 

 cumulating.^ Concerning the pathways involved, however, 

 little is known. The physiological importance of the nerve 

 supply of the pars intermedia has been clearly suggested by 

 experiments in amphibia and certain other cold-blooded ani- 

 mals. Here again, however, not much is known about the lo- 

 cation of the innervating (efferent) neurones, although Hair 

 found that some fibers of the supraoptico-hypophysial tract 

 can be traced to the pars intermedia in the cat. Our best in- 

 formation deals with the nerve supply of the pars neuralis. 

 Especially in recent studies employing physiological and 

 morphological technics it has been possible to demonstrate 

 the great dependence of the pars neuralis on certain hy- 

 pothalamic nuclei, particularly the paired supraoptic nuclei. 

 Necessarily, then, the greater part of the discussion will be 

 concerned with the pars neuralis. Much of the review of the 

 physiological experiments, together with an additional dia- 

 gram of the nervous connections between the hypothalamus 

 and the pars neuralis, will be found in chapter x. 



The diagram reproduced as Figure 3 represents the opinion 

 of Roussy and Mosinger on the innervation of the pituitary 



^ Such as the effect of light on the secretion of gonadotropic hormone in birds 

 and in one mammal, the ferret. Strong, diffuse electrical stimulation causes the 

 liberation of gonadotropic hormone (ovulation) in the rabbit. See also the report 

 of CoUin and Hennequin (1936) on changes in the pars glandularis of the rabbit fol- 

 lowing bilateral extirpation of the superior cervical ganglia (see also chap. iii). 



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