SUPRARENAL GLANDS 



407 



cords of the zona fasciculata are perpendicular to the surface; they end 

 below in a network, the zona reticularis. In this deeper portion the cells 



Capsule- 



Zona glomerulosa. - 





\ Cortex 



Medulla. 



Zona fasciculata 



Zona reticularis. 



Cell cords of the medulla. - 



Nerve in cross section 

 Ganglion cells .... 



Bundles of smooth muscle 

 fibers in cross section. 



Veins. 



FIG. 420. SECTION OF A HUMAN SUPRARENAL GLAND, x 50. 



become pigmented, so as to form a dark brown band visible without 

 magnification. Fat vacuoles are here smaller or absent, as seen in Fig. 

 421, which shows also the close 

 relation between the cells and 

 the vascular endothelium. In 

 portions of the suprarenal gland 

 where the medulla is lacking, 

 the zonae reticulares of the op- 

 posite sides come together, form- 

 ing the core of the organ. 



The medulla is composed of 

 chromaffin cells arranged in 

 strands and masses which unite 

 to form a network, with lacunar 

 veins filling the interstices (Fig. 

 420). The cells contain an 

 abundant granular protoplasm, 

 but they tend to shrink, even in 

 well-preserved specimens, so 



armour crpllatP CFicr FIG. 4- FROM A SECTION OF THE SUPRARENAL GLANB 



appear steiiaie ^r ig. OF AN ADULT, x 360. 



