THE OVAEY. 



1313 



Descent of the Ovary. Like the testes, the ovaries at first lie in the abdominal 

 cavity, and only later assume a lower position. At birth the ovary lies partly in the 

 abdominal, and partly in the pelvic cavity ; soon, however, it takes up a position entirely 

 within the pelvis minor. As in the male a gubernaculum is present in the early stages of 

 development. The ligament of the ovary represents the upper part of the gubernaculum 

 which is developed within the plica testis inferior in the male, and the round ligament of the 

 uterus represents the inferior part, which is formed within the plica inguinalis (see p. 1295). 

 It is a rare abnormality for the ovary, instead of entering the pelvis, to take a course similar 

 to that of the testis, and pass through the inguinal canal into the tissue of the labium majus. 



Structure of the Ovary. The ovary is for the most part composed of a connective 

 tissue, called the stroma ovarii, richly supplied by blood-vessels and nerves. The stroma 

 contains very numerous spindle-shaped connective tissue fibres, and some elastic tissue. 

 The surface of the ovary is covered by a layer of epithelium, which is composed of 

 columnar cubical cells, and is continuous with the epithelium of the peritoneum 

 forming the mesovarium. The ovarian epithelium is a persistent portion of the 

 germinal epithelium of the embryo which covers the genital ridges, and from which the 

 ova and other cells of the Graafian follicles are derived. The position in which it be- 

 comes continuous with the peritoneum can usually be distinguished as a fine white line 

 near the hilum of the ovary. Shining through the epithelium of the fresh ovary (except 



Down-growths of epithelium 

 Germinal epithelium 



Ovum with its investing cells 



Stratum granulosum 



Nests of epithelial cells Ovarian stroma Vesicular ovarian follicle Ovum 



Liquor folliculi 

 Cumulus oophorus 





1031. A. DIAGRAMMATIC REPRESENTATION OF THE MANNER IN WHICH THE FOLLICULI VESICULOSI 



ARISE DURING THE DEVELOPMENT OF THE OVARY. B. DIAGRAM ILLUSTRATING THE STRUCTURE 



OF A RIPE OR VESICULAR OVARIAN (GRAAFIAN) FOLLICLE. 



in old age) are usually to be seen a variable number of small vesicles the folliculi 

 oophori vesiculosi (O.T. Graafian follicles), in which the ovula, or ova, are contained. The 

 number of follicles visible, and also the size which each follicle reaches before it ruptures 

 and sheds its contents, is by no means constant. When a follicle ruptures and discharges 

 the ovum its walls at first collapse, but later the cavity becomes filled with extravasated 

 blood and cellular tissue of a yellowish colour. The resulting structure, called a corpus 

 luteum, slowly degenerates unless impregnation has taken place, in which case it develops 

 and becomes larger during pregnancy. As it atrophies the cells of the corpus luteum 

 disappear, and the structure, losing its yellow colour, receives the name of corpus albicans. 

 After a time the corpus albicans completely disappears. Owing to the periodic rupture 

 of the folliculi vesiculosi, the surface of the ovary, which is at first smooth and even, 

 becomes in old age dimpled and puckered. 



A section through the ovary, especially in young children, presents in its superficial 

 part a somewhat granular appearance, which is due to the presence of enormous numbers 

 of small follicles, or collections of epithelial cells, embedded in the connective tissue 

 near the surface of the ovary. The larger follicles lie deeper in the stroma, but when 

 they become fully developed they pass towards the surface, where the ripe follicles are 

 often seen slightly projecting and ready to burst. In the deepest part of the ovary the 

 blood-vessels are most numerous, and here also some smooth muscle fibres are found. 



The ova and the other cells that compose the folliculi vesiculosi are derived originally 

 from the germinal epithelium which covers the developing ovary in the embryo. The 

 epithelium, at first simple, grows down into the underlying tissue in the form of branching 



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