Final answer:
The monthly changes in the female gonads are known as the ovarian cycle, which is a roughly 28-day process involving oogenesis and folliculogenesis, closely related to the menstrual cycle.
Step-by-step explanation:
The series of monthly changes that occur within the female gonads are referred to as the ovarian cycle. This cycle is an approximate 28-day cycle of changes in the ovary consisting of a follicular phase and a luteal phase. The ovarian cycle is made up of several processes including oogenesis (the production of female gametes or eggs) and folliculogenesis (the maturation of ovarian follicles).
Oogenesis begins with ovarian stem cells known as oogonia, which multiply via mitosis. Before birth, these cells become primary oocytes that are arrested in the first stage of meiosis I until puberty. As a woman approaches menopause, the number of primary oocytes declines.
The menstrual cycle is closely connected but not identical to the ovarian cycle. It involves the development of the uterus lining in preparation for a fertilized egg, a process which works in tandem with ovarian changes, including the maturation of a follicle, ovulation, and the development of the corpus luteum.