The amniotic sac is filled with amniotic fluid and consists of taut tissue, the membranes of the eggs. It is the protective cover that surrounds the fetus in the womb (uterus) during pregnancy. The amniotic sac and amniotic fluid together form the habitat of the unborn child.
Origin
At the end of the third weeks, the fetus is about 4 millimeters long and takes on more and more shape and becomes increasingly vulnerable. After fertilization, the developed cell cluster is initially called a blastocyst. The blastocyst consists of two different cell layers, the inner and outer.
From the inner cell group the child finally develops. The outer cell group forms a fold with the middle cotyledon over the growing embryo. The amniotic cavity is increasingly formed, which later becomes the amniotic sac.
The amniotic cavity grows back while the embryo grows downwards. The distance between the amniotic cavity and the embryo becomes greater and greater during pregnancy and increasingly fills with fluid, the amniotic fluid. The amniotic sac finally lines the uterus from the inside. It has approximately the size and thickness of a balloon. It is very flexible and elastic and therefore adapts well to the later movements of the baby in the womb.
Function of the amniotic sac
The amniotic sac has several important functions during pregnancy. These include the formation of the amniotic fluid. The amniotic fluid is produced by the inner cells of the amniotic sac and is secreted by the uterus.
Another very important function is to protect the unborn child. The amniotic sac completely encloses the embryo so that germs, viruses or bacteria have no chance of entering the amniotic sac from outside and possibly causing an infection. In addition, the elasticity of the amniotic sac protects the embryo very well from external shocks. It can happen that pregnant women bump into something with their thick belly. This impact is then absorbed very well by the amniotic sac and the amniotic fluid, so that the newborn baby does not suffer any damage and hardly notices anything of the impact.
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