syncytiotrophoblastjának

The syncytiotrophoblast is a multinucleated tissue that forms the outer layer of the developing placenta. It originates from the fusion of the mononucleated cytotrophoblast cells, which are the stem cells of the trophoblast. This fusion process occurs early in pregnancy, starting around the second week after fertilization. The syncytiotrophoblast is crucial for implantation, as it invades the uterine wall.

A primary function of the syncytiotrophoblast is to facilitate nutrient and gas exchange between the mother and the fetus. It forms the barrier between maternal blood in the intervillous space and fetal blood within the villous capillaries. This barrier allows for the efficient transfer of oxygen, carbon dioxide, nutrients, and waste products. The syncytiotrophoblast also produces essential hormones, including human chorionic gonadotropin (hCG), progesterone, and estrogen, which are vital for maintaining the pregnancy.

The syncytiotrophoblast is characterized by its large size, lack of distinct cell boundaries, and the presence of numerous nuclei within a continuous cytoplasm. It is a dynamic tissue that continuously renews itself. Aging syncytiotrophoblast cells shed into the maternal circulation, forming syncytial knots, and this shedding process is thought to play a role in placental development and function. Disruptions in syncytiotrophoblast formation or function are associated with various pregnancy complications, such as preeclampsia and intrauterine growth restriction.