1274 



PHYSIOLOGY 



Embedded in the stroma but especially numerous just underneath the epithe- 

 lium, are a vast number of ' primordial follicles.' These are formed during 

 fcetal life by downgrowths of the germinal epithelium. Of the cells pro- 

 longed in this way from the germinal epithelium, some undergo enlargement 

 to form the primordial ova, while the others are arranged in a single layer 

 of flattened nucleated cells, the ' follicular epithelium,' as a sort of capsule 

 to i!he ovum. Of the primordial follicles, about 70,000 are to be found in 

 the ovary of the newborn child, During the first twelve to fourteen ye'ars of 



^ 7 t ^-^-^ , v 



S^Sitx 



A 





Fio. 574. Graafian follicle of mammalian ovary. (PRENANT and BOUIK.) 



ov, ovum; dp, discus proligerus; Iq.f, liquor follicnli; ch, theca; 



gr, mombrana granulosa. 



life they remain in a quiescent condition. With the onset of puberty one or 

 more of the primordial follicles begin to develop. Indeed, this development 

 may be regarded as the causative factor in the various phenomena which 

 are characteristic of puberty in the female (v. p. 1269). The first stage in 

 the growth of the follicle is a proliferation of the follicular epithelium, the 

 cells of which become cubical and are arranged in (several layers round the 

 ovum. At one point in the mass of Jcells surrounding the ovum, a cavity 

 appears filled with fluid, the liquor foil '>'!',. The epithelium thus becomes 



