3.9: Understand the Roles of Oestrogen and Progesterone in the Menstrual Cycle

MENSTRUAL CYCLE: Changes that occur within female reproductive system for pregnancy to be viable

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• Each menstrual cycle lasts roughly for one month and begins at puberty before ending with menopause
• Pituitary hormones (FSH and LH) are released from Pituitary gland and acts on Ovaries to develop Egg cell
• Ovarian hormones (Estrogen and Progesterone) are released from Ovaries and act on Uterus to prepare for pregnancy

MENSTRUAL CYCLE:

MENSTRUAL CYCLE

Diagram showing the Levels of Hormones during the Menstrual Cycle

PROCESS:     1. FSH (Follicle - Stimulating Hormone) Pituitary Gland secretes FSH to cause Egg cell to mature and develop Additionally, FSH stimulates Ovaries to secrete Oestrogen      2. OESTROGEN   Ovaries secrete Oestrogen to stop the secretion of FSH, ensuring only one Egg cell matures in a cycle Additionally, Oestrogen stimulates Pituitary gland to secrete LH      3. LH (Luteinizing Hormone) Pituitary gland secretes LH to stimulate Ovulation - the release of a mature Egg cell from Ovary Additionally, LH stimulates Ovaries to release Progesterone      4. PROGESTERONE Progesterone thickens blood vessels in the Uterus to maintain the Uterus Lining for Pregnancy If fertilised Egg cell is implanted in the Uterus lining, Progesterone will ensure Uterus lining is thick and rich in blood vessels to cushion fertilised Egg cell to maintain pregnancy