148 



MICROSCOPIC ANATOMY OF THE ORGANS. 



shows a radial structure, which is caused by the radial arrange- 

 ment of the connective-tissue framework (Fig. 105). In the 

 medulla the cells are arranged less regularly. The following 

 description is based largely on an account of the structure of 

 the gland given by Flint. 



The whole gland is surrounded by a capsule (Fig. 106), 

 which is composed largely of reticulum. Elastic fibres and 

 smooth muscle cells are also present. 



The cortex may be divided into three layers : 1, the zona 

 glomerulosa ; 2, the zona fasciculata ; and 3, the zona reticu- 

 laris (Figs. 105-107). 



1. The zona glomerulosa is made up of cylindrical epithelial 



FIG. 100. 



Capsule 



Blood-vessel in 

 a septum 



Zona glomerulosa 



Zona fasciculata 



WM 



veftsBi'a 



*:.' 



From the cortical substance oft lit- adrenal of a <lo<r. 



245. 



cells arranged in more or less coiled columns separated by 

 strands of connective tissue derived from the capsule (Figs. 106, 

 107). The nuclei are situated in the middle part of the cell 

 bodies. They are oval or round, and stain deeply. 



2. The zona fasciculata consists of smaller polygonal cells 

 arranged in anastomosing columns whose long axes are at right 

 angles to the surface of the capsule. The columns are sepa- 



