THE ANATOMY OF THE PITUITARY BODY 



of that caring for the pars neurahs. At least in mammals hke 

 the monkey and man, it is now beheved that there is no close 

 vascular connection between the pituitary body and the 

 hypothalamus. There is, therefore, little basis for postulating 

 important effects of pituitary hormones on diencephalic cen- 

 ters. 



However, certain hypothalamic centers, particularly the 

 supraoptic nuclei, supply efferent fibers to the pars neuralis. 

 If this innervation is completely severed, the pars neuralis 

 atrophies and ceases to secrete its hormone in some if not all 

 mammals. The cells of nuclei like the supraoptic nuclei mor- 

 phologically are very different from most neurones but can- 

 not yet be described as glandular cells of the diencephalon. 

 The innervation and especially the central connections of the 

 pars glandularis and pars intermedia are matters requiring 

 intensive investigation. 



The function and therefore the morphological significance 

 of the pars tuberalis are unknown. 



The pars intermedia, the source of the chromatosome-dis- 

 persing hormone in many animals, is, of course, a part of the 

 pars buccalis. In certain animals lacking a pars intermedia, 

 either because of its failure to differentiate or because of its 

 regression in later life, the lobe's characteristic hormone is 

 secreted by the pars glandularis. 



The oxytocic and vasopressor hormones of the pars neuralis 

 probably are not secreted or derived from cells of the pars 

 buccalis such as invading basophils. Such invasion of the pars 

 neuralis is not etiologically related to diseases like essential 

 hypertension or eclampsia. Certainly, the hyaline bodies of 

 Herring do not represent the hormones either actually or in a 

 preformed state. A newly described glandular cell in the pars 

 neuralis appears to be the source of the diuresis-inhibiting 

 (vasopressor) hormone. 



A great variety of changes in the pars glandularis has been 

 related to the endocrine equilibrium of the animal, whether 

 occurring normally or owing to a deficiency or to the injec- 



[29] 



