460 



THE DUCTLESS GLANDS 



The parenchymal cells of the organ are ovoid elements which 

 are closely packed about the walls of the blood vessels in groups 

 or short columns inclosed by delicate sheaths of connective tis- 

 sue. The origin and function of these cells are unknown. The 

 organ is embedded in the dense connective tissue at the tip of 

 the coccyx. 



VI. HYPOPHYSIS CEKEBKI (Pituitary Body) 



This body consists of two distinct lobes, an anterior and a 

 posterior. The posterior is largely composed of nerve elements ; 



the anterior is more distinctly 

 glandular. This difference in 

 structure is doubtless depend- 

 ent upon the genesis of the 

 organ, the posterior lobe being 

 developed as an outgrowth 

 from the second cerebral ves- 

 icle or diencephalon, the an- 

 terior arising as a diverticulum 

 from the oral cavity of the 

 fetus. 



The cellular elements of 

 the posterior lobe include 

 ependyma cells, neuroglia cells, 

 small nerve cells, and a few 

 epithelioid cells (Berkley *). 

 The anterior lobe consists of 

 epithelial cells which occur in 

 small groups and irregular 

 strands, between which are 

 broad sinusoidal capillaries. 

 The cells are ovoid in shape, 

 of a finely granular appearance, 

 and possess large spheroidal 



nuclei. Some of them, the chromophile cells, are somewhat acido- 

 phile and granular ; the chief cells, on the other hand, show no 

 special affinity for acid dyes. In this they resemble the cells of 

 the parathyroid gland. Occasionally the cell columns of the 

 pituitary gland assume a tubular or follicular character and in 



FIG. 365. FROM A SECTION OF THE HY- 

 POPHYSIS CEREBUI OF A DOG. 



a, blood vessels ; 6, endothelium of the 

 vascular wall ; c, glandular epithelium, 

 x 300. (After Szyuionowicz.) 



Johns Hop. Hosp. Rep., 1895. 



