Macrophages come in to clean up dead tissue.
Astrocytes form scar tissue in the form of astoglial fibers. Infarcts are due to the occlusion of an artery of the Circle of Willis or one of its branches or a vein by a thrombus or embolus. Atherosclerosis is the major cause of cerebral vascular disease causing thickening and partial or complete occlusion of arterial lumina leading to thrombosis, due to low flow or sudden expansion of the arteriosclerotic plaque by hemorrhage or rupture of the plaque. Emboli arise from diseases of the heart with thrombi on abnormal heart valves or mural thrombi over areas of transmural or subendocardial myocardial infarcts. Cerebrovascular disease is the third leading cause of death after heart disease and cancer.