GROWTH OF THE EGG IN THE OVARY 



21 



Fig. 9. The ovarian cycle in mammals. The egg 

 develops within the walls of a follicle. The follicle 

 increases in size and a follicular fluid accumulates. 

 When the pituitary hormones reach certain concen- 

 trations the follicle wall breaks and the ovum is lib- 

 erated. The empty follicle becomes filled with a spe- 

 cial type of cell and forms a solid body, the corpus 

 luteum. If fertilization does not ensue, the corpus 

 luteum degenerates and a small body of scar tissue 

 marks the site. 



DEGENERATION OF 

 CORPUS LUTEUM 



SCAR TISSUE 



