The afterbirth

The placenta is the organ that communicates the fetus from the mother's body, otorvalsya of the uterus after birth the fetus. Part of the placenta include the placenta (see), fetal membranes, and the umbilical cord (see). Fetal membrane to form an embryo SAC, away from the edge of the placenta and can easily be separated into its constituent pieces - chorion (hairy sheath), the amnion (water cover) and part of the decidual, shell (see), adjacent to the fertilized egg.
Rorion - the outer shell of the fertilized egg (embryo); coated fibers, grow into the uterine lining, participating in the formation of the placenta. Rorion starts to function in the early stages of embryogenesis, through trophic, respiratory, excretory and protective functions. Rorion, developing of trophoblast and mesoblast, forms the outer shell of the fetal bag. At the beginning of the development of it is covered with avascular the villus. At the end of the first month of pregnancy in them grow into the vessels of the allantois. On the second month of pregnancy begins atrophy of the chorionic villi, turned into the uterine cavity. On the other side of the chorion, which turned to the wall of the uterus, NAP grow, branched, forming fertile part of the placenta. Each NAP consists of a Central core formed by connective tissue passing it capillaries. Outside the NAP covered epithelium, consisting of two layers: the syncytium and cells Lunghezza, Epithelial cover CVS has the ability to melt be the uterine lining, thereby nadacia (implementation in the endometrium) a fertilized egg, and further delivery to the fetus nutrients.
The amnion - the lining of fetal bag, in which is the fruitsurrounded amniotic fluid (see); develops from the walls of the amniotic bubble. The amnion is a thin the shell is lined epithelium. The amnion, adhering to the chorion, covers and internal (fruit) the surface of the placenta, enters the umbilical cord, dobryva it in the form of case. Part of the fetal membranes, located in front of predlagay part of the fruit and filled the front waters, called the fetal bubble. Fetal bladder during childbirth, first passing along with amniotic waters and internal Zev of the cervical canal, promotes normal period of disclosure. The whole is born of the placenta and fetal membranes is of great importance for succession and postnatal periods. Therefore, after delivery of the placenta should be examined carefully, checking the integrity of the placenta and fetal membranes. At rupture of membranes should be checked for light - not whether to rupture a blood vessel, which suggests trapped in the uterus incremental slice of the placenta and the need for manual examination of the uterus. If all the vessels of the whole, and the shell is torn, the manual examination of the uterus is not shown as delayed shell later will go with lahiyy (see the Postpartum period). Cm. also Succession period.

The placenta is the organ of communication of the fetus with the body of the mother otorvalsya of the uterus after birth the fetus. Among obstetricians and anatomists, until recently, there is no consensus on what part of the ovum are part of the placenta. It is wrong to equate the concept of placenta with the placenta, which, though part of it, but is an independent body with complex vnutricletocny function.
Some authors under the placenta (secundinae) understand the placenta, or a children's place, fleecy and water shell and the umbilical cord. Other authors in addition to the fetal membranes (shell, which is the fruit together with the umbilical cord and waters) belong to the past and a part of the falling shell, predlagay to the fertilized egg (decidua basalis), but do not include the umbilical cord. If the placenta to understand all that comes out of the uterus after birth the fetus, it is necessary to include in the composition of the placenta placenta (see), the egg shell, the falling part of the shell and the umbilical cord.
The falling shell reaches the greatest power on 3-4-th month of pregnancy. In the future gradually becomes thinner the melt actions applied to it Vorsin. Compact layer with vessels disappears; in deep spongy layer, which is in contact with CVS, corrosive wall extensive network of capillaries, formed majorsince space, which are immersed chorionic NAP. Towards the end of pregnancy falling shell turns into a thin plate with the remains of glandular layer adjacent to the muscle layer of the uterus. The surviving parts of the shell in places where vessels, give partitions (septa placenthae)that penetrate into the interior of the fruit part of the placenta, dividing it into separate segments. Decidual shell (see) is the parent part of the placenta. All Royal surface of placenta covered with a thin, grayish-white film, which is the cloth falling shell.
Water shell, or the amnion, develops very early from the walls of the amniotic bubble. The amnion is growing rapidly, amniotic cavity fills a large part of the blastocyst cavity, and then membranes. Fetal bladder is part of the fetal membranes, located in front of predlagay part, filled the front waters. Omnianalysis bag presses wasting yolk bubble to the chorion, clothing while outside, forming the umbilical cord. Towards the end of pregnancy water sheath coated with cylindrical or cubic epithelium, fused with a smooth chorion (chorion leve), from which it can be separated, except for the portion that goes to the umbilical cord. It is considered the shell water avascular education. However, in the early stages of pregnancy in the wall of the amnion discovered a dense network of lymphatic capillaries and blood vessels of the type of capillaries beneath the epithelium, connective the basis of the amnion.
Hairy sheath, or the chorion, formed by the merger of trophoblast with mesoderm of allantois. Already at the 2nd month. pregnancy it from all sides covered with villi. On the 3rd month. part of the chorion, adjacent to navorochennoy shell loses NAP, turning into a smooth chorion (chorion leve). NAP on the part adjacent to the decidual shell, strongly proliferate and form of fruit a part of the placenta. Each NAP consists of a Central core (of fibrous connective tissue) and capillary vessel. Outside the rod is covered with epithelial cover, consisting of two layers - syncytium and cells Langhans. Epithelial cover CVS has the ability to melt the uterine lining for implantation of the egg, and in future - fabric falling shell, revealing its clearance blood vessels. This process is of great physiological significance in the entire pregnancy (see): through the cells of epithelial cover CVS from the mother's blood is taken nutrient
material to the fetus. Matters and enzymatic activity of the epithelium of the villus.