REPRODUCTIVE FUNCTIONS. 



909 



tion of the ovum, which has already been fnlly considered. Some points 

 in the development of the ovum and its attendant phenomena neverthe- 

 less deserve consideration. 



The ova are developed in the matrix of the ovary. The latter con- 

 sists of a connective-tissue frame-work supplied with blood-vessels, 

 nerves, and lymphatics, whose surface is covered with a layer of columnar 

 epithelium — the remains of the germinal epithelium. The most super- 

 ficial layer of the ovary is called the tunica albuginea and contains no 

 ova ; but if section be made of the ovary, throughout its entire sub- 

 stance will be found small follicles varying from one-hundredth to one- 

 thirtieth of an inch in size. In- each of these Graafian follicles will be 

 found an ovum in different stages of development. Immediately after 



< 



Fig. 414.— Section of an Ovary. [Landois.) 



e germ epithelium ; 1, large-sized follicles ; 2 2, smaller sized follicles ; o, ovum within a Graafian follicle ; 

 v v, blood-vessels of the stroma ; g, cells of the membrana granulosa. 



birth the ovary contains immense numbers of ova — in the human female 

 infant from forty thousand to seventy thousand. The ova develop from 

 the layer of germinal epithelium which originally completely surrounded 

 the ovary. At different intervals on the surface depressions form, which 

 serve to carry in a layer of germinal epithelium to form the so called 

 ovarian tubes. These tubules gradually become deeper and deeper, and 

 contain within their interior large, single, spherical cells, with a nucleus 

 and a nucleolus, in addition to the small, columnar cells lining the .tube.- 

 As the tubules extend into the ovary the growth of the stroma of the 

 ovary serves to constrict the orifices of the tubules, and finally their 

 openings become completely obliterated, and the tubule, which originally 

 began as a pocket-shaped depression on the surface of the ovary, now 



