Overview Decreased tissue oxygen results in reduced ATP production and cell death Can occur in two forms Red hemorrhagic due to the re-entry of blood into the tissue following cell death associated with loose tissues with collaterals such as liver (portal and systemic) lungs (pulmonary and bronchial) intestine (portal and systemic) lysis of an emboli that initially obstructed blood flow Pale pale due to continued inability of blood to re-enter the infarcted area associated with solid tissues with single blood supply such as heart kidney spleen atherosclerotic thrombi that cannot be lysed due to continued reformation at site of obstruction