The female body is endowed with two ovaries, located in the lower abdomen on either side of the uterus. The ovaries produce eggs. In addition, as the organs of internal secretion, the ovaries produce hormones, the most famous of which are estrogen and progesterone.
Important! Ovaries accumulate eggs at the stage of prenatal development girls. The two ovaries of a newborn, there are hundreds of thousands of eggs. However, they are inactive until the onset of puberty, that is, until about 12 years. During this time, a certain number of cells die, but still 300 000 - 400 000 full eggs.
Since puberty and before menopause, a woman will experience from 300 to 400 menstrual cycles, which resulted in the same Mature oocytes that can be fertilized. According to a French family statistics, women on average give birth to 2 children. This means that only 2 (or 3) of hundreds of thousands of oocytes carrying out their mission! To better understand the process of ovulation, contact your imagination. Each ovary is like prunes. During the menstrual cycle in the Mature one of the many eggs. She dozed in the stillness, and waited for the signal 15, 30, or 40 years. Under the influence of follicle-stimulating hormone (FSH) in the pituitary and endocrine glands on the lower surface of the brain, begins to grow follicles (SAC) selected for ovulation in this cycle, the egg. The diameter of the follicle at the beginning of the cycle does not exceed 1 mm, and 2 weeks later he reaches 20 mm
With the growth of the follicle on the surface of the ovary bulge formed by the middle of the cycle is increased to the size of grapes. Inside the "grapes" (follicle) contains a liquid and a small "seed" in diameter 0, 1 mm. In the middle of the cycle, approximately 12 days after the start of menstruation, the pituitary gland releases a large amount of luteinizing hormone (LH). After 36 hours after ovulation. Still, the egg nucleus slumber wakes up and prepares its chromosomes for possible fertilization.
Chromosomes located in the nucleus, are carriers of the genetic code. The purpose of fertilization - the fusion of two sex cells (gametes), originating from opposite-sex individuals. All human cells contain 46 chromosomes. Therefore, the two gametes must form a new cell, also containing 46 chromosomes. Simply adding it would be 92 chromosomes, but this would lead to a biological error, the effect of which would be the cessation of reproduction. Therefore, each partner should halve their number of chromosomes (23). The egg reduction in the number of chromosomes occurs after pituitary luteinizing hormone. For this conversion to a 20 - 36 hours.
Preparing itself to receive the sperm, the egg is pushed to the periphery, in a small pouch called the first polar body, half of its chromosomes. Meeting with the sperm must occur within a certain time. If this happens before the egg is ready to receive sperm, as well as not able to divide their chromosomes; if later, it risks missing the period of maximum readiness for fertilization. We already know that in most cases, no fertilization, despite the fact that women during the childbearing period Matures 300 - 400 oocytes.
Following 14 days after ovulation, the second part of the cycle, taking place in the preparation of the mucous membrane of the uterus, forming a "soft bed" for the fetus. All training is in vain if conception has not occurred, and its biological effects will be together with menstrual bleeding. But in one of the ovaries is already maturing hope again - rising new "grapes"...
What happens if the expectation is justified? Released from the follicle, the egg, with the reduction of chromosomes, into the fallopian tube, which with their soft fringes connected with the ovary. Fringe reminiscent of the open flower on the end of the stem. And his vivid petals on the go capture the egg, like a bee collecting nectar.
The date of egg and sperm usually occurs in the fallopian tube. The fallopian tube is a cylindrical muscular organ inside it is lined with mucous membrane, coated fibers and contains glands that produce secretions. This structure facilitates the movement of eggs and (if fertilization occurred) of the embryo into the uterus, where he prepared a place.
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