A Female monthly cycle - Follicular Phase

"This phase starts on the first day of your period. During the follicular phase of the menstrual cycle, the following events occur:

Two hormones, follicle stimulating hormone (FSH) and luteinizing hormone (LH) are released from the brain and travel in the blood to the ovaries.
The hormones stimulate the growth of about 15-20 eggs in the ovaries each in its own "shell," called a follicle.
These hormones (FSH and LH) also trigger an increase in the production of the female hormone estrogen.
As estrogen levels rise, like a switch, it turns off the production of follicle-stimulating hormone. This careful balance of hormones allows the body to limit the number of follicles that complete maturation, or growth.
As the follicular phase progresses, one follicle in one ovary becomes dominant and continues to mature. This dominant follicle suppresses all of the other follicles in the group. As a result, they stop growing and die. The dominant follicle continues to produce estrogen. "conjuglascience.