In the female reproductive system, the ovaries are responsible for producing and releasing eggs. This process is regulated by various hormones, primarily estrogen and progesterone. These hormones are produced by the ovaries themselves and the pituitary gland in the brain, and they work together to control the menstrual cycle.
Estrogen plays a crucial role in the early stages of the menstrual cycle. As estrogen levels rise, they stimulate the growth and development of follicles within the ovaries. Each follicle contains an immature egg. When estrogen levels reach a peak, it triggers the release of luteinizing hormone (LH) from the pituitary gland. LH causes ovulation to occur, releasing a mature egg from the ovary.
Progesterone, on the other hand, becomes dominant in the second half of the menstrual cycle. It helps in preparing the uterus for the possible implantation of a fertilized egg. If fertilization does not occur, progesterone levels decrease, leading to the shedding of the uterine lining during menstruation.
The interplay of estrogen and progesterone ensures the precise timing and coordination of ovulation and other events in the menstrual cycle. Hormonal imbalances or disruptions can affect ovulation and contribute to irregular menstrual cycles or fertility issues.