Angiogenesis is the formation of new blood vessels from pre-existing vessels. There are two main types of angiogenesis: sprouting angiogenesis and intussusceptive angiogenesis. Sprouting angiogenesis involves the activation of endothelial cells by growth factors, degradation of the extracellular matrix, endothelial cell proliferation and migration, and formation of new loops and branches to form new vessels. Intussusceptive angiogenesis involves the extension of endothelial cell junctions into the vessel lumen to split existing vessels. Angiogenesis plays an important role in development, wound healing, and diseases like cancer by supplying tumors with nutrients and oxygen needed for growth.