The origin of menstruation

The female body has certain mysteries, because the uterus is the most important part of the female body, and women are able to conceive and become pregnant. Menstruation is a normal physiological cycle for women every month, and the origin of menstruation is very complicated. Menstruation is also usually a sign of a woman's physical health. Menstruation is very important for women and affects their pregnancy. What is the origin of menstruation?

1. The Origin of Menstruation

The female internal reproductive organs consist of the ovaries, uterus, and fallopian tubes. The main function of the ovaries is to produce eggs and synthesize ovarian hormones, while the uterus and fallopian tubes are reproductive organs. The ovaries contain hundreds of thousands of follicles, each of which contains one egg.

Before puberty, the follicles are essentially non-functional. During puberty, under the action of gonadotropin from the anterior pituitary gland, immature follicles gradually develop and synthesize estrogen. When the follicle matures and ovulates, the follicle wall collapses, the cells become larger and yellower, and are called the corpus luteum. It synthesizes estrogen and produces progesterone.

As the ovaries change, the endometrium is also affected and undergoes corresponding cyclical changes. Estrogen causes the endometrium to thicken, the endometrial cells to increase in number and size, and the arterioles in the interstitium to become more tortuous and spiral, which is called the proliferative endometrium. After ovulation, due to the combined effects of estrogen and progesterone, the endometrium becomes edematous, the glands produce a large amount of mucus and glycogen, and the thickness of the endometrium increases from 1 mm to 6 mm, which is called the secretory endometrium.

If the egg released at this time is fertilized, the fertilized egg is transported to the uterus through the fallopian tube for development, which is called pregnancy. The pregnancy tissue synthesizes a chorionic gonadotropin, which supports the continued development of the corpus luteum of the ovary. If the egg is not fertilized, the corpus luteum will atrophy and stop secreting estrogen and progesterone about 14 days after ovulation. At this time, the blood vessels in the endometrium contract, the endometrium necrotizes and falls off, causing bleeding and forming menstruation.

2. What is menstruation?

The main components of menstruation are blood, endometrial tissue fragments and various active enzymes and biological factors. Among them, fibrinolytic enzyme makes menstrual blood liquid and prevents it from coagulating, and prostaglandins play the role of contracting the uterus. Medically speaking, only the reproductive cycle experienced by primates (including humans) is called menstruation.