The Smith County Veteran Services Office will be closed Monday through Monday, August 15-22, 2016. The Smith County Veterans Service Office will be closed Monday through Monday, August 15-22 for training, and will reopen on Tuesday, August 23 for normal business hours.
The first differentiation event in the formation of the placenta is the formation of trophoblasts, specialized epithelial cells, that ultimately form a physical connection between the embryo and the uterus. Allocation of cells to the trophoblast lineage is dependent on their position at the morula stage.
The placenta is formed by cells that originate from the foetus and is therefore the first of the foetal organs to develop. What does the placenta do? The placenta contains a complex network of blood vessels that allow the exchange of nutrients and gases between the mother and the developing foetus. The blood supply of the mother does not actually mix with that of the foetus; this exchange occurs by diffusion of gases and transport of nutrients between the two blood supplies (see figure). The transfer of nutrients and oxygen from the mother to the foetus, and waste products and carbon dioxide back from the foetus to the mother, allows the growth and development of the foetus throughout pregnancy.