THE PITUITARY BODY 



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proper or anterior lobe, the pars anterior, the posterior lobe, pars nervosa, 

 and an intermediate epithelial zone known as the pars intermedia. 



The pars anterior or glandular lobe of the pituitary and also the pars 

 intermedia are derived from tissue that has its embryological origin from 

 the epithelial pouch of the roof of the buco-pharyngeal cavity. The pars 

 intermedia differentiates out of this common mass and comes to invest the 

 infundibular portion, apparently sending cells into its trabeculae. Three 

 types of cells have been described for the pars amerior; i, neutrophiles, 2, 

 acidophiles, and 3, basophiles. The pars nervosa consists of a loose neuroglia 

 like network arising out of the base of the third ventricle. The net exhibits 

 open spaces more or less filled with ingrowths of pars intermedia cells. 

 The pars intermedia (see Fig. 319) shows cavities filled with colloid being 



FIG. 318. Mesial sagitta 1 section of the pituitary. B, third ventricle. AL and PL. 

 anterior and posterior lobes respectively. (Gushing and Goetsch.) 



discharged into the spaces of the pars nervosa. It is thought that this 

 colloid may be directly or indirectly the source of the active hormones of 

 the posterior division of the pituitary. 



a. The Function of the Pituitary. The whole problem of the function of 

 the pituitary body has been extensively studied physiologically and sur- 

 gically by Gushing. This author has obtained concordant results by his 

 operative study on dogs, and by the operative and clinical treatment of a 

 long series of human patients. That the pituitary is absolutely necessary 

 to life is now recognized. A number of functional disturbances have been 

 traced to abnormal states of this organ, and evidence is accumulating to 



