Final answer:
The loss of primordial follicles throughout life is described by the process of oogenesis, which is part of the ovarian cycle leading to a reduction in the number of primary oocytes until menopause.
Step-by-step explanation:
The loss of primordial follicles throughout life is related to oogenesis. Oogenesis is the process whereby the ovarian stem cells, called oogonia, multiply by mitosis and form primary oocytes in the fetal ovary before birth. These primary oocytes remain in a suspended state until puberty, at which point they resume development. However, the quantity of primary oocytes declines over time, from around one to two million at birth to roughly 400,000 at puberty, and ultimately to zero at menopause. This continual decline in primary oocyte numbers through a woman's life is a natural part of the ovarian cycle, which leads to menopause, defining an end to the female reproductive phase.