Answer:
The corpus luteum is formed from the ovary. The pituitary gland increases its production of the second hormone, luteinizing hormone (LH). This second hormone allows the mature egg to rupture from the ovary (called ovulation) and enter into the uterine tube. The postovulatory phase has begun. LH also encourages the formation of a "scar" within the ovary. This "scar" is called the corpus luteum, and it produces the hormone progesterone.