What is the use of the corpus luteum formed after ovulation?

The body structure of women is different from that of men. Take the reproductive cells in the body for example. Women's reproductive cells are eggs, while men's reproductive cells are sperm. The egg is released once a month, and the number of sperm is much greater than the number of eggs. However, every time a woman ovulates, her body will have some special feelings. So, what is the role of the corpus luteum formed after ovulation?

After ovulation, the remaining follicular wall collapses, and the connective tissue and capillaries of the follicular membrane extend into the granulosa layer. Under the action of LH, it evolves into a larger cell cluster rich in capillaries and with endocrine function. It appears yellow when fresh and is called corpus luteum.

structure

If the corpus luteum is not fertilized, it is called the menstrual corpus luteum. If fertilized, it is called the corpus luteum of pregnancy. After ovulation, the follicle wall collapses and the granulosa layer forms wrinkles inward, accompanied by bleeding from the capillaries in the inner layer of theca. After the wound heals, the follicular cavity is closed and filled with serous fluid and blood. At the same time, the basement membrane collapses, and connective tissue and blood vessels grow into the granulosa layer. Under the action of luteinizing hormone (LH), the granulosa cells and the cells in the inner layer of theca divide and proliferate. The cells are polygonal, with yellow granules and lipid droplets in the cytoplasm, which is yellow in color, hence the name corpus luteum. The majority of luteal cells are granulosa cells, which are large, lightly colored, and secrete progesterone; theca luteal cells are small, most of which are located at the periphery of the corpus luteum, have fewer cells, and their nuclei and cytoplasm are darker than those of luteal cells, and secrete estrogen. The length of time the corpus luteum exists depends on whether the released egg is fertilized or not. If the egg is not fertilized, the corpus luteum only lasts for two weeks before it atrophies and is replaced by a connective tissue scar, the corpus albicans. If the egg is successfully fertilized and pregnancy begins, the corpus luteum continues to grow and then slowly atrophies after six months of pregnancy or even longer.

The corpus luteum is made up of two types of cells:

Granulosa lutein cell: Granulosa lutein cell is transformed from follicular granulosa cells. It is located in the center of the corpus luteum. The cells are large and lightly stained. They mainly secrete progesterone.

Theca lutein cell: located around the corpus luteum, with an uneven surface. The cells are small, darkly stained, and primarily synthesize estrogen.

effect

The corpus luteum of the ovary secretes progesterone, which is a natural progestin that has a significant morphological effect on the estrogen-stimulated endometrium in the body and is necessary for maintaining pregnancy.

Its main functions are: 1. In the later period of the menstrual cycle, it causes the glands in the uterine mucosa to grow, the uterus to become congested, and the endometrium to thicken, thus preparing for the implantation of the fertilized egg. After the fertilized egg is implanted, it produces the placenta, reduces the excitability of the pregnant uterus, inhibits its activity, and allows the fetus to grow safely. 2. Working together with estrogen, it promotes full development of the breasts in preparation for milk production. 3. It closes the cervix, reduces and thickens the mucus, and makes it difficult for sperm to penetrate. In large doses, it has a negative feedback effect on the hypothalamus, inhibiting the secretion of pituitary gonadotropin and producing an ovulation-inhibiting effect. 4. Can inhibit smooth muscle contraction.