According to the sources, the menstrual cycle involves specific hormonal and uterine changes across different phases. In the Luteal (Secretory) phase, the parts of the Graafian follicle remaining after ovulation transform into the corpus luteum, which then secretes large amounts of progesterone . Other options are incorrect because: (1) Menstruation and the Proliferative phase involve the breakdown and regeneration of the endometrium (the inner glandular layer), not the myometrium (the middle muscular layer) ; and (2) While LH and FSH do peak during ovulation, progesterone levels only rise significantly after the corpus luteum is formed post-ovulation .