Patient's question:
How is menstruation formed, and what is ovulation?Doctor's answer:
Menstruation refers to the physiological phenomenon of cyclic uterine bleeding in women. A cycle lasts for 28-30 days, with each lasting 3-5 days. Humans reproduce offspring through a. The place where human fetuses grow and develop is the mother's reproductive organ—the uterus. To allow a new life to "implant" and grow in the uterus, the uterine lining must undergo cyclical changes.Girls entering puberty begin to secrete two hormones from their ovaries: estrogen and progesterone, which stimulate the uterine lining to change. This change occurs in three phases.
(1) Proliferative Phase: Before mature eggs are produced, the ovaries begin to secrete estrogen, stimulating the uterine lining to thicken.
(2) Secretory Phase: When a mature follicle in the ovary ruptures and releases an egg, the follicle itself transforms into a corpus luteum, which secretes progesterone. This hormone further thickens and congests the uterine lining, preparing it to receive and nourish a fertilized egg. Because the secretory glands of the uterine lining extend and become full of nutrients during this phase, it is called the "secretory phase."
(3) Menstrual Phase: If the egg is not fertilized after being released, the corpus luteum gradually atrophies. At this time, the ovaries can only secrete small amounts of estrogen and progesterone, causing the uterine lining to lose its ability to maintain its state and shed. Blood and fragmented mucosa are expelled from the uterine cavity through the vagina—this is what is known as "menstruation."
This menstrual blood flow is regular, occurring once a month, hence the term "menstruation." Menstruation plays a cleansing role in the shedding of the uterine lining.