Blood vessel formation

Blood vessels are made of a thin layer of ECs. As part of the circulatory system, blood vessels play a critical role in transporting blood throughout the body. Consequently, ECs have unique functions such as fluid filtration, homeostasis and hormone trafficking. ECs are the most differentiated form of an ESC. Formation of new blood vessels occurs by two different processes: vasculogenesis and angiogenesis.  The former requires differentiation of endothelial cells from hemangioblasts and then the further organization into a primary capillary network. The latter occurs when new vessels are built from preexisting blood vessels.