THE SUPRARENAL GLANDS 



551 



At the inner border of the /.ona fasciculata the connective! tissue 

 bundles pass insensibly from the regular columnar arrangement of this 

 layer into a reticiilar maze. The resulting cell groups are of very irregu- 

 lar form and compose the innermost cortical layer, the /one retictdaris. 

 This layer is the 

 thinnest and least 

 distinct of the 

 three zones of the 

 e o r t e x. It can 

 often be more read- 

 ily distinguished by 

 the highly pig- 

 mented condition 

 of its cells, than by 

 the mere form of 

 its cell columns. 

 In man it passes 

 almost insensibly 

 into the medulla ; 

 in many animals 

 e.g., the dog, cat, 

 and pig there is a 

 sharp demarcation 

 between the zona 

 reticularis and the 

 medulla, produced 

 by a thin mem- 

 branous layer of 



FIG. 479. PHOTOMICROGRAPH OF SUPRARENAL GLAND OF 

 connective tissue DOG. 



which apparently A, loose areolar connective tissue of outer portion of 

 results from the capsule containing two large (G) and several small gan- 

 c. p , , glia; c, capsule proper; g, zona glornerulosa; F, zona fascic- 



ulata; R, zona reticularis of cortex; M, medulla, showing 

 tral ends of the the large central vein (V;. 



fibrous bands in the 



cortical stroma. Such a membranous septum is usually wanting in the 



human adrenal. 



The connective tissue stroma of the adrenal consists of a delicate 

 vascular network, which in the cortex contains very few if any elastic 

 fillers, l-'linl (11)00) has shown that this connective tissue is, in large 



part, at least, a reticiilar tissue. The capsule consists of dense bundles 

 35 



