38 



PHYSIOLOGY 



CHAP. 



XI. The Pituitary Body (hypophysis cerebri) consists of two 

 distinct parts or lobes (Fig. 7). The posterior lobe, which is 

 greyish-yellow, is an outgrowth from the third ventricle of the 

 brain ; it has no glandular structure and is probably a rudimentary 

 organ of no importance in vertebrates at any rate. The anterior 

 lobe, on the contrary, which is reddish in colour, and is much 

 more highly developed than the posterior lobe, has quite a distinct 

 function, and is derived from the primitive pharynx. At a certain 

 point in embryonic development it appears as a pouch, which is 

 empty at first, and subsequently fills by the development of 



FIG. 7. Hypophysis or pituitary body. A, lateral aspect, showing relations with sella turcica. 

 B, posterior aspect. C, sagittal section, a, anterior lobe of hypophysis (pituitary body 

 proper) ; ft, posterior or nervous lobe ; c, pineal peduncle ; d, optic chiasnia ; c, inf undibulum ; 

 /, optic foramen ; g, quadrilateral plate of sphenoid ; h, sulcus occipitalis. 



epithelial cells disposed in groups or columns, which recall the 

 structure of the parathyroids. Two kinds of cells can be distin- 

 guished, the chief cells and the chromaphile (Fig. 8). 



The latter have a special affinity for stains, and react like 

 " colloid " substances ; they are probably more developed than the 

 chief cells, and serve for the secretion of a hyaline substance, 

 in analogy with the epithelia of the thyro- parathyroid system 

 (Lothringer). The secretion passes into the lymphatic spaces of 

 the surrounding connective tissue, and also in part to the blood- 

 vessels, in which it may for short distances replace the blood 

 entirely (Pisenti and Viola). 



Experiment on the functions of the pituitary body has led to 



