And these Corianic extensions are known as Coryonic villi, and they basically form a structure that looks like a capillary bed. So as the circulatory system, as the cardiovascular system of that growing embryo develops, these Corianic extensions begin to become populated with the blood vessels. And so inside these Corianic villi, if we take a cross section, we'll see this population of blood vessels. And these embryonic blood vessels eventually connect to the umbilical arteries and the umbilical veins found inside the umbilical cord. And those structures, those blood vessels eventually directly connect to the circulatory system of that fetus. Now, once those digestive enzymes begin to break down the endometrium, the connective tissue, they also actually break down the vascular tissue.