Number of oocytes?!
Until recently, it was assumed that women were born with a certain number of eggs, which could not change in the course of life. According to this belief, it was thought that infertility would result when the last egg was ovulated. However, current research shows that this is not true: even in adulthood, there are probably still egg stem cells in the ovaries that are capable of dividing. In principle, the production of new egg cells is apparently still possible in adult women, but more detailed studies are still needed.
Ovulation
Of the many oocytes in the ovary, only one develops approximately every four weeks (according to the female cycle) to a stage where it is finally released from the ovary and absorbed by the fallopian tube. This phenomenon is called ovulation. Like the entire cycle, this process is controlled by hormones. In the fallopian tube, the egg is now either fertilized by a sperm, whereupon it can implant itself in the lining of the uterus and a pregnancy begins. If this does not happen, the egg reaches the uterus unfertilized, which means that the thick mucous membrane at this point is not needed there and is rejected by the body.This then leaves the female body together with the egg through the vagina and menstruation occurs.
Fertilization of the egg cell
Fertilization, also called fertilization, is the fusion of the female egg with the male sperm. In humans, this can happen naturally through insemination during sexual intercourse and is possible around the time of ovulation. However, the development of modern medicine allows fertilization to be carried out artificially, mostly outside the body.
There are several methods available for this; the basis for all of them is the extraction of sperm, which is carried out by masturbation or surgically from the testicles. In vitro fertilization is carried out in a test tube. In this procedure, eggs must be extracted from the woman.
The egg and the sperm can now either be brought together in a test tube and find their way to each other on their own, so that the actual fertilisation can take place without external help. After in vitro fertilisation, the fertilised egg, usually two at a time, must be transferred to the lining of the uterus. The chances of the egg implanting and becoming pregnant are about 40% and depend on some biological parameters such as the woman’s age.
However, it is also possible to perform intracytoplasmic sperm injection, which is mainly performed in case of less motile sperm. In this procedure, a sperm is injected directly into the egg cell using a pipette. Furthermore, there is the intrauterine insemination. In this method, the extracted sperm are placed in the woman’s uterus during the period of ovulation, so that fertilization takes place in the woman’s body.
