The menstrual cycle is the reproductive cycle of female humans and other animals, particularly certain primates (e.g. apes and monkeys), shrews, and bats.1 It is described through the ovarian cycle and the uterine cycle.
The ovarian cycle is comprised of phases characterized by the changes in the ovarian follicles. It is comprised of the phases: (1) follicular phase, (2) ovulation, and (3) luteal phase. The follicular phase is the first phase of the ovarian cycle. In this phase, a dominant ovarian follicle will reach maturity and contain the ovum. The ovum will then be released from the ruptured ovarian follicle into the oviduct in the next phase, which is the ovulation. In the last phase of the ovarian cycle, which is the luteal phase, the remaining parts of the dominant follicle will transform into the corpus luteum through the action of the luteinizing hormone as well as the follicle stimulating hormone. The formed corpus luteum, in turn, secretes progesterone that suppresses the production of the luteinizing hormone and follicle stimulating hormone, as well as making the endometrium receptive to blastocyst implantation when pregnancy occurs. In the absence of pregnancy, the corpus luteum goes through luteolysis, which occurs at the end of the luteal phase.
1 Lopez, K. H. (2013). Human Reproductive Biology. Academic Press. p. 53.