What distinguishes ischemic strokes from hemorrhagic strokes?

The distinction between ischemic and hemorrhagic strokes is fundamentally based on their underlying causes. Ischemic strokes occur when a blood vessel that supplies blood to the brain becomes blocked, typically due to a blood clot. This blockage deprives brain tissue of essential oxygen and nutrients, leading to cell death and neurological deficits. On the other hand, hemorrhagic strokes are characterized by the rupture of a blood vessel, resulting in bleeding within or around the brain. This can create pressure on brain structures and can also compromise blood flow, causing additional damage.

The other options do not accurately reflect the nature of these strokes. High blood pressure can indeed contribute to hemorrhagic strokes, but it is not a direct cause of ischemic strokes, and many other factors, such as clots from the heart or arteries, can lead to ischemic events. The claim that ischemic strokes affect only one hemisphere while hemorrhagic strokes affect both is misleading, as both types can affect one side or both sides of the brain depending on the area impacted by the stroke. Lastly, while ischemic strokes may sometimes ensue from cardiovascular issues, they are not directly caused by heart attacks, which further complicates the assertion made in that option.