Yolk sac

The first fruit-feeding organ is the yolk sac.The norm or, most accurately, the optimal time of appearance is 15-16 days of development of the fetal egg. This substance is formed from an endoblastic vesicle, which is a derivative of the embryoblast. This small formation, which is in direct contact with a fertilized egg, is unique in its composition and functions.

It is interesting thatthe yolk sac gives rise to the formation of blood cells and a fine capillary network. Already from 18-20 days of development of the fetal egg in it you can find a small bloody mesh.

Thus, this body is one of the most importantfor the future baby. After all, until the placenta is formed with a dense blood network, all the nutrients the embryo will receive from the yolk formation.

Already by the 30th day of development of the yolk sactransports primary germ cells to the embryo - the baby's sexual system begins to form. Many people think that it is at this time that they decide who will be born, a boy or a girl. However, young parents need to know that the sex of the baby is decided at the time of fertilization, and at all other stages of development only the organs are formed, in accordance with genetic information.

Numerous functions of the primary feederbody does not end there. To all other things, before the 6th week of the development of the embryo, the yolk sac also performs the function of the liver, or more precisely it synthesizes proteins: alpha-fetoprotein, transferrin, alpha2-microglobulin.

It must be remembered that this body is still anda kind of envelope of the fetus, until the moment when its immune system can not itself fight against possible pathogenic microorganisms. The fact is that the primary organ of the fetus can independently produce macrophages in the fight against infection. Thus, it protects the fertilized egg from negative impact from the outside.

Such a system of patronage and nutrition of the fetusvery short, by the end of the first trimester, the yolk sac degenerates and turns into a small peri-ubic formation. By this time, all of its functions are assumed by the formed placenta and other organs of the fetus.

I must say that if for some reasonthe yolk formation begins to regress until the placenta or other important formations are formed, then miscarriage or intrauterine fetal death is possible. That is why there are certain time intervals when it is necessary to undergo ultrasound.

How can you find a yolk sac and determine its functionality?

Women who are preparing for the birth of a baby,probably already read in the literature that with ultrasound, the yolk sac can only be seen from the 6th week of fetal development, and in some cases a little later. This may be due to the location of the fetal egg or the sensitivity of the equipment.

If you are told by ultrasound that the yolk sac is not visualized, you do not need to panic right away. Listen to the doctor to the end. Surely he will explain everything to you.

There are many variants of pathologypregnancy, in which the bag is reduced too soon, or it is not sufficiently developed. A woman should understand that even if it is possible to maintain such a pregnancy, the probability of developing vices in such a baby is doubled.

It must be said that the observation of developmentyolk formation before the 12th week of pregnancy can tell how the development of the fetus will proceed and with what complications doctors and parents may face.

There is such a thing as "frozenpregnancy "is a pathology of the yolk sac, in which it is small and non-functional. The fruit reaches a certain stage of development, and for further growth of nutrients is no longer enough. In such a situation, it is necessary to perform cleaning of the uterine cavity together with hormonal therapy.