There are several types of strokes caused by blocked or ruptured blood vessels in the brain. Ischemic strokes are caused by blocked arteries, cutting off blood flow and oxygen to brain tissue. Hemorrhagic strokes occur when blood vessels rupture, either within the brain itself (intracerebral hemorrhage) or in the space surrounding the brain (subarachnoid hemorrhage). Transient ischemic attacks (TIAs) involve a temporary blockage but no permanent damage. Risk factors for strokes include hypertension, smoking, heart disease, and diabetes.