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 develops throughout the embryonic period and during the first several weeks of the fetal period; placentation is complete by weeks 14â16. As a fully developed organ, the placenta provides nutrition and excretion, respiration, and endocrine function ([link] and [link]).