Corpus Luteum Thin Section

In the human ovary, follicles, the precursor cells of ova, undergo a complex monthly maturation cycle. At birth of a female approximately 400,000 ovarian follicles have been developed, but only about 400 enter into ovulation during a woman's childbearing years. The corpus luteum is the enlarged remnant of the secondary (Graafian) follicle following monthly ovulation, and it features vacuoles associated with the fat-soluble steroids, estrogen and progesterone.