1988 



HUMAN ANATOMY. 



Blood-vessel 



Connective- ^jV^ 



tissue stroma 







l^^?^^jKg;^,:>\vv;- ' 



Muscle 



bundles that extend in all directions (chiefly, however, obliquely vertical to the 

 surface) and are seen cut in different planes. Immediately beneath the germinal 

 epithelium covering the surface, the stroma-elements are disposed with greater reg- 

 ularity and form a compact superficial stratum, the tunica albiiginea. Embedded 

 within the stroma lie the most characteristic components of the cortex, the eg^-sacs 

 or G7'aafian follicles. These are seen in different stages of development, but for the 

 most part are small, inconspicuous, and immature, in the human ovary being much 

 fewer and less prominent than in many other mammals. Corresponding with their 

 stages of development the egg-sacs may be di\'ided into primary , growing, and ma- 

 turing follicles. In general, the youngest lie nearest the surface, the more advanced 



deeper and towards the 

 Fig. 1686. medulla, while those ap- 



'''i^^^.Ni-..^, V proaching maturity ap- 



pear as huge vesicles 

 that occupy not only 

 the entire thickness of 

 the cortex, but often 

 produce marked eleva- 

 tion of the free surface. 

 The medulla, the 

 vascular zone of the 

 ovary, consists of loosely 

 disposed bundles of 

 libro-elastic tissue sup- 

 porting the blood-ves- 

 sels, lymphatics, and 

 nerves. In the mature 

 organ, with the excep- 

 tion of the encroaching 

 ripening Graafian folli- 

 cles, egg-sacs are not 

 found within the me- 

 dulla. The larger ves- 

 sels are accompanied by 

 bundles of involuntary 

 muscle prolonged from 

 the utero-ovarian ligament through the mesovarium and the hilum into the medulla. 

 The veins are particularly large and appear in sections as huge blood-spaces of irregu- 

 lar outline in consequence of their tortuosity and plexiform arrangement. 



Follicles and Ova. — The xmrnaXwYe primary follicles (folliculi oophori primarii) are micro- 

 scopic in size (from .04-.06 mm. in diameter) and vary greatly in number, the estimate for the 

 two ovaries of young adults being placed at approximately 35,000 (Bonnet). Each follicle 

 consists of the centrally situated young egg (ovulum) surrounded by a single layer of flat- 

 tened epithelium or mantle cells (Fig. 1685). Immediately outside the latter lies the stroma, 

 in the interstices of which the young egg-sacs are lodged. The primary ova are approximately 

 spherical and measure from .035-.045 mm. in diameter in ordinary sections, but a third more in 

 the fresh unshnmken condition (Nagel). They possess a finely granular cytoplasm, a centrally 

 placed spherical nucleus, about .016 mm. in diameter, and a nucleolus. The primary ova may 

 remain for years, sometimes from early infancy to advanced age, practically unchanged, until 

 they undergo either atrophy, as do most of them, or further growth leading, under favorable 

 conditions, to the development of the mature sexual cell. Of the thousands of primary eggs 

 contained in the ovaries just before puberty, only comparatively few attain perfection. Sooner 

 or later, but at some uncertain time, the primary follicles enclosing ova destined for complete 

 development enter upon a period of active growth, the earliest indication of which is the con- 

 version of the flat mantle cells of the egg-sac into a single layer of cuboid epithelium. 



In addition to increasing size, \he growing follicles are distinguished by rapid prolifera- 

 tion of the cuboid epithelium, which results in the production of a stratified follicular epithe- 

 lium that surrounds the ovum. Outside these polygonal elements the stroma becomes con- 

 densed into a connective-tissue envelope or theca (theca folliculi). Increasing in thickness, the 

 latter is subsequently differentiated into two layers, an outer (tunica externa), consisting of con- 



Section of medulla of ovary, showing- numerous blood- 

 vessels and fibro-muscular stroma. X 75- 



