THE FEMALE REPRODUCTIVE ORGANS. 



225 



FIG. 266. 



maining central portions of the ovary, in which the blood-vessels are 

 conspicuous constituents. 



The bulk of the organ consists principally of the stroma, together 

 with the contained blood-vessels and the Graafian follicles. 



The ovarian stroma is a peculiar form of connective tissue dis- 

 tinguished by the great number of its spindle-cells, which, while dis- 

 tributed through all parts of the organ, are especially closely packed 

 in the cortex, particularly near the periphery. 



The cortical stroma, arranged in variously-directed bundles, is 

 greatly condensed immediately beneath the germinal epithelium, the 

 zone of condensed tissue appear- 

 ing as a distinct peripheral layer, 

 the so-called tunica albuginea ; 

 the latter, however, does not rep- 

 resent an independent structure, as 

 does the sheath bearing the same 

 name in the testicle, but only a 

 peripheral band of the stroma of 

 especial density. 



The most important constit- 

 uents of the cortex are the 

 Graafian follicles, which are 

 exclusively limited to this part 

 of the ovary, where they occur 

 in all stages of development. 

 The youngest and least matured 

 Graafian follicles are plentifully 

 scattered through the outer part 

 of the cortex, where in many ani- 

 mals, as the cat and the rabbit, 

 they form almost a complete 

 zone. The most immature fol- 

 licle consists of the ovum sur- 

 rounded by a single layer of flat- 

 tened cells, the progenitors of the 

 membrana granulosa, outside of which lie the cells of the general 

 stroma, without the intervention of a special limiting membrane. 

 Among the immature follicles are others in various stages of more 

 advanced development, in which the ovum is embraced by two or 

 more rows of polygonal cells ; around such ova the stroma is con- 

 centrically disposed, a condition foreshadowing the membrana gran- 

 ulosa and the theca of later stages. The cells which surround the 

 ovum by their division give rise to the numerous elements lining the 

 follicle; they were originally derived from the germinal epithelium 



15 



Section of human ovary, including cortex : a, 

 germinal epithelium of free surface ; b, tunica 

 albuginea ; c , peripheral stroma containing im- 

 mature Graafian follicles (of) ; e, well-advanced 

 follicle from whose wall membrana granulosa 

 has partially separated ; f, cavity of liquor 

 folliculi ; g, ovum surrounded by cell-mass con- 

 stituting discus proligerus. 



