Final answer:
A stroke, including both ischemic and hemorrhagic types, is a medical condition resulting from the loss of blood flow to the brain, causing cell death. Ischemic strokes are more common and can be treated if addressed quickly with medications like rtPA.
Step-by-step explanation:
A stroke, also known as cerebrovascular accident or brain attack, occurs when there is a loss of blood flow to a part of the brain, causing brain cells to die. There are two main types of stroke: ischemic and hemorrhagic. An ischemic stroke occurs when blood vessels are blocked or narrowed, often due to an embolus like a blood clot or fat deposit, causing a reduction in blood flow to the brain. This event can also happen due to a thickening of the blood vessel wall or a drop in blood volume in the brain, called hypovolemia. Ischemic strokes are more common and can lead to the devastation of the affected brain region. The affected region includes the ischemic core, which is irreversibly damaged and the ischemic penumbra, an area of impaired but potentially salvageable brain tissue. Treatments, like recombinant tissue plasminogen activator (rtPA), aim to restore blood flow and must be administered shortly after the stroke onset to be effective.