432 



MANUAL OF HISTOLOGY. 



called blood-vascular glands, but their function is not known. 



They belong to the ductless variety of glands. 



Each suprarenal body consists 

 of a capsule inclosing the paren- 

 chyma, which shows a cortical and 

 medullary substance. The cap- 

 sule is formed of ordinary connec- 

 tive tissue containing many deli- 

 cate elastic fibrils. Externally it 

 is surrounded by loose connective 

 tissue, containing a greater or less 

 proportion of adipose tissue, and 

 internally it sends out trabeculse, 

 which traverse the entire organ, 

 thus constituting and completing 

 its frame-work. 



The cortical substance, as its 

 name implies, occupies the exter- 

 nal portion of the suprarenal body. 

 It has an average thickness in man 

 of 0.28 to 1.12 mm., is of a yellow- 

 ish color, and may be divided into 

 three layers or zones. The lim- 

 its of demarcation between these 

 layers are much less marked, 

 however, than the corresponding 

 boundary line between the corti- 

 cal and medullary portions. In 

 the human being the external layer 

 of the cortex is distinctly separate 



from the middle one, but the latter shows no such sharp limit 



against the innermost layer. 



The cortex is a friable substance, 



and its broken surface presents 



a striated appearance. Owing to 



rapid post-mortem changes, the 



cortex in man is usually found 



to be separated from the medul- 

 lary portion by a dirty brownish 



SUbstanCe, Containing modified 



blood and cortical corpuscles. 



PIG. 184. Perpendicular section through 

 the suprarenal capsule of man : 1, cortex ; 2, 

 medulla; a. capsule; 6, layer of outer cell- 

 groups ; c, layer of cell-trabeculae (zona fasci- 

 culata); d, layer of inner cell-groups ; e, med- 

 ullary substance ; /, transverse section of a 

 vein. Eberth. 



FIG. 185. Single cells and cell-groups of the 

 Human suprarenal cap- 



