Ammionkalvo

Ammionkalvo, also known as the amniotic sac, is a thin, membrane-like structure that encloses the developing embryo or fetus during pregnancy. It is one of the key fetal membranes that form during early embryonic development. The amniotic sac is filled with amniotic fluid, which surrounds and protects the fetus.

The amniotic sac serves several vital functions. Firstly, it provides a protective cushion against external physical shocks and trauma, preventing injury to the developing baby. Secondly, the amniotic fluid helps to maintain a stable temperature around the fetus, shielding it from fluctuations in the mother's body temperature. Thirdly, it allows the fetus to move freely within the uterus, which is crucial for muscle and bone development. The fluid also prevents the umbilical cord from being compressed, ensuring a continuous supply of nutrients and oxygen to the fetus. Furthermore, the amniotic fluid plays a role in preventing infection by acting as a barrier against microorganisms.

The amniotic sac typically ruptures towards the end of labor, commonly referred to as "breaking of the waters." This event signifies that the baby is close to being born. The amniotic sac and fluid are expelled from the uterus along with the placenta after the birth of the baby, an event known as the afterbirth. In some cases, the amniotic sac may remain intact during birth, a phenomenon known as being "born in the caul."