The uterus bleeds once a month, which is called menstruation.
So, why can the uterus produce menstruation once a month?
The ovaries are responsible for laying eggs, ovulating and producing hormones. The hormones secreted by the ovaries are mainly estrogen, progesterone and androgens. Among them, estrogen is very important for the maintenance of sexual organs, secondary sexual characteristics and ovarian cyclic development and function. Progesterone mainly acts on the uterus to ensure the progress of pregnancy. Androgens increase sexual desire and are also involved in the regulation of follicle growth and egg maturation. When a woman reaches puberty, her follicles mature. With the cooperation of luteinizing hormone, the follicles secrete estrogen and stimulate the endometrium to undergo proliferative changes. The amount of progesterone gradually increases, causing the endometrium to thicken, the glands to increase and grow, and become curved, and the blood vessels to become spiral, which is called the proliferative endometrium. This is approximately the 11th to 14th day of the menstrual cycle. At this time, estrogen peaks, and a large amount of estrogen acts on the hypothalamus, causing the pituitary gland to release a large amount of luteinizing hormone, thereby prompting mature follicles to ovulate. After ovulation, the ruptured follicle forms the corpus luteum. The corpus luteum secretes progesterone, which, under the combined action of estrogen, causes the endometrium to enter the secretory phase. If there is no fertilization at this time, the corpus luteum will atrophy, the secretion of progesterone and estrogen will decrease, and the endometrium will not be supported by sex hormones, and will undergo necrosis, shedding, and menstruation. This is how the uterus produces menstruation.
This article is provided by Baidu Reading and is excerpted from \”The Clear \”Conception\” Plan\” Author: Sun Jianqiu and Xie Yingbiao