The placenta as the third brain.

The placenta has enormous genetic endowments, comparable to those of the brain and ovary. The molecular, cellular and vascular arrangements are designed for directing the traffic of biochemical and nutritional flow preferentially to the fetus. The architect and landscape of this powerful organ, with a predetermined life span of 40 weeks, serves as a modulator between compartments via local, nearby and long-distance communications through its hormonal signals. Thus, the placenta may be viewed as the third brain, which links the developed (maternal) and developing (fetal) brains.