THE SUPRARENAL BODIES. 



1803 



'^A%«i Capsule 

 Cortex 



medulla, includes the net-works of epithelial elements formed by the union of the cyl- 

 inders. The cells throughout the cortex are very similar, being rounded polygonal 

 elements .01 5-. 020 mm. in diameter, and very often contain fat granules. Those 

 composing the zona fasciculata are largest, while those within the reticular zone are 

 more or less pigmented and responsible for the darker tint of this portion of the cortex. 



The medullary substance consists chiefly of net- works composed of anastomosing 

 cords of epithelial cells from .020-. 036 mm. in diameter; in addition there are numer- 

 ous blood-vessels, particularly veins, and many bundles of nerve-fibres with ganglion- 

 cells. The protoplasm of the medullary cells is finely granular and possesses an 

 especial affinity for chromic acid and its salts, staining yellow or brown. They 

 vary from polyhedral to columnar in form, and often border large blood- and lymph- 

 spaces. The cells of the medulla are 



more prone to undergo post-mortem Fig. 1525. 



change than those of the cortex. 



Vessels. — The chief arteries 

 supplying the organ are the three 

 suprarenal or capsular arteries, — the 

 middle from the aorta and the su- 

 perior and inferior from the phrenic 

 and renal arteries respectively. They 

 break up into a dozen or more fine 

 branches before reaching the organ, 

 which they enter at various points, 

 some penetrating directly into the 

 medulla, others terminating in the 

 cortex. The latter form a superficial 

 capillary net-work within the cap- 

 sule, from which continuations pass 

 between the cortical cell-columns, 

 around which they constitute capil- 

 lary net-works. The medulla is di- 

 rectly supplied by arteries destined 

 for the interior of the organ. These 

 soon break up into capillaries which 

 surround the medullary cords and 

 pass over into an unusually rich 

 plexus of veins. The latter claim as 

 tributaries the venous radicles of the 

 zona reticularis and impart to the 

 medulla in general a spongy charac- 

 ter. The veins form a rich plexus 

 about the organ, communicating 

 freely with those of the kidney. The 

 chief vein of the right suprarenal 

 passes into the inferior vena cava and that of the left one into the renal. The lyjn- 

 phatics are numerous, the chief trunks accompanying the arteries. In addition to the 

 superficial net-works in the outer part of the cortex, the medulla contains many 

 deeper lymphatics in the vicinity of the larger veins. 



Nerves. — The very rich supply is derived principally from the solar and renal 

 plexuses. The number of medullated fibres would imply that many come through 

 the splanchnic nerves. Branches probably come also from the vagus and the phrenic 

 (Bergmann). Within the capsule lies a superficial ple.xus from which small bundles 

 of nerve-fibres enter the cortex, between the cell-columns of which they form plexuses, 

 chiefly for the walls of the blood-vessels. The greater number of the nerves, how- 

 ever, pass to the medulla, where they unite into coarse plexuses, from which finer 

 twigs are distributed to the vessels and the cords of medullary cells surrounding the 

 veins. Dogiel has traced the terminal filaments between the epithelial elements. 

 Numerous ganglion-cells lie within the medulla. Sometimes they occur in groups 

 along the larger nerve-bundles ; at other times they are encountered as isolated ele- 



Capsule 



Section of suprarenal body including entire thickness of organ, 

 showing general arrangement of cortex and medulla. X 27. 



