THE CENTRAL NERVOUS SYSTEM. 



331 



FIG. 355. 



polygonal cells (13-17 /*), whose granular protoplasm frequently 

 contains fat-particles in addition to clear nuclei. The arrangement 

 of the cortical elements varies at different levels, the resulting 

 disposition giving rise to the three 

 divisions of the cortex recognized as 

 the zona glomerulosa, the zona fas- 

 ciculata, and the zona reticularis. 

 The cells forming the first of these are 

 grouped as oval masses, those of the 

 middle layer are disposed as long 

 cylindrical groups, and those of the 

 third stratum are irregularly arranged 

 as anastomosing cords supported 

 within a reticulum of connective tissue. 

 The zona reticularis is distinguished 

 from the other cortical layers by the 

 pigmented condition of its cells. The 

 various groups of cellular elements are 

 separated from one another by delicate 

 fibrous septa, continuations from the 

 outer connective-tissue envelope ; the 

 larger septa support the capillary net- 

 works which surround the groups of 

 cells. 



The medulla contains granular, fre- 

 quently feebly-pigmented, polygonal 

 cells arranged as cords and irregular 

 net - works within a framework of 

 highly vascular connective tissue. Nu- 

 merous ganglion - cells occupy the 

 central portions of the medulla, along 

 with a rich net-work of non-medullated nerve-fibres and the con- 

 spicuous venous channels. 



The blood-vessels of the organ divide within the capsule into 

 numerous smaller branches, which enter the parenchyma along the 

 fibrous septa ; capillary net-works surround the cell-groups of 

 both cortex and medulla. The veins of the medulla are of large 

 size and unite to form trunks which make their exit at the central 

 hilus ; the larger radicles are accompanied by longitudinal bundles 

 of non-striped muscle. 



The nerves of the suprarenal body are remarkable for their num- 

 ber and size ; they bear the arteries company within the septa to 

 reach the medulla, where they form an intricate plexus composed 

 chiefly of non-medullated fibres. Ganglion-cells occur along 



Section of human suprarenal body : 

 a, fibrous capsule ; b, zona glomeru- 

 losa ; c, zona. fasciculata ; d, zona reti- 

 cularis ; e, medullary cords ; f t venous 

 channel ; g, ganglion-cells'. 



