1. Ovarian follicle
  2. Granulosa cells
  3. Ovum or egg

Ovaries produce Estrogen, and ProgesteroneThecal endocrine cells and granulosa cells of the ovarian follicle produce Estrogen. Estrogen plays a role in the development of female sex characteristics and helps to regulate the female reproductive cycles (Ovulation and Menstruation).  After ovulation, Progesterone is produced by the remaining granulosa cells.  If the ovum (egg) is fertilized, the corpus luteum will remain and continue to release Progesterone to prepare the endometruim for implantation and pregnancy.  If the egg is not fertilized, the corpus luteum will degenerate, stop producing Progesterone, and turn into the corpus albicans.