100 FOLLICULAR DERIVATIVES IN VERTEBRATES III 



£. the granulosa-lutein cell produces a sexual hormone 

 (oviductin in Anamnia; progesterone in Mammalia), which 

 acts upon the adnexa; 



C. only in exceptional cases do granulosa-lutein cells 

 persist as interstitial cells; in most cases they succumb (Fig. 

 71 B). 



c. The post -ovulation corpus luteum is formed as follows: 



a. a rupture-factor (possibly supported nervously) causes 

 rupture of the follicle; 



fi, the ovum is carried away either fertilised or not; 



7. a pituitary factor causes granulosa hypertrophy (gran- 

 ulosa luteinisation) ; 



d. a second pituitary factor may in some cases cause theca- 

 hypertrophy (theca luteinisation) ; 



£. the granulosa-lutein cell produces a sexual hormone 

 acting upon the adnexa; 



;. the theca-lutein cell also produces a hormone of its 

 own, which acts upon the adnexa; 



7/. the theca-lutein cells may persist as interstitial cells, 

 whilst the granulosa cells succumb (Fig. 71C). 



The calyx is formed as follows:— 



a. a rupture factor causes ovulation of the follicle; 



/5. the ovum is carried away whether fertilised or not; 



7. the pituitary cannot act on the granulosa cells; 



d. the pituitary may produce, in the most extreme case, a 

 slight theca-hypertrophy; 



£. the granulosa degenerates, possibly under the influence 

 of thecal substances; 



C. the theca turns into granulation tissue, and serves to 

 close up the ovulation wound. 



It will be seen from the above analysis that there is a 

 distinct difference between thecal atresia and the granulosa 

 formations (pre-ovulation corpus luteum), and that the 

 three glandular follicular derivatives, corpus atreticum, pre- 

 and post-ovulation corpus luteum, are the opposites of the 

 non-glandular calyx-forms. 



