What is gangrene?

Tissue death: Gangrene is the death of tissue due to lack of blood supply. There are a number of different causes for this lack of blood supply such as embolus to an artery, atherosclerotic occlusion of an arterty, trauma to an artery or bacterial/toxic damage to the arterioles and tissues.

Lack of blood: gangrene happens when the supply of blood is not enough to keep the tissue alive. When this happen the cells of the area begin dying to decrease the demand of blood to the area and increase the blood more proximally.