Placenta Looks Like a Tree

Schematic representation of placental circulation

The placenta is similar with a tree planted to a pot. As a tree takes deep root in the soil, the vessels from the umbilical cord, which inserts to the chorionic plate, stretch toward the intervillous space by progressively branching from intermediate villi to terminal villi. It finally forms several local regions called the 'cotyledon', consisting of villous trees, at the maternal surface called 'decidua basalis'. The intervillous space is filled with maternal blood and perfused through spiral arterioles, which enables the feto-maternal metabolic transports.

Further readings

1. Rampersad, R., Cervar-Zivkovic, M., & Nelson, D. M. (2011). Development and Anatomy of the Human Placenta. In The Placenta (pp. 17–26). Wiley-Blackwell.
2. You, W. (2016). How Does the Placenta Look Like. Brain In God.