2-Minute Neuroscience: Stroke

Stroke is the second leading cause of death in the world. In this video, I discuss the two main categories of stroke: ischemic and hemorrhagic stroke. I describe how these types of stroke occur, how they can damage brain tissue, and some common symptoms of stroke.

TRANSCRIPT:

Welcome to 2 minute neuroscience, where I explain neuroscience topics in 2 minutes or less. In this installment I will discuss stroke.

Stroke occurs when blood flow to part of the brain is suddenly disrupted. It is the second leading cause of death in the world. There are two major categories of stroke: ischemic and hemorrhagic.

Ischemia is a term that refers to a reduction in blood supply to a bodily tissue, and ischemic strokes occur when blood flow to a part of the brain is blocked or restricted. This is most commonly due to a blood clot blocking a blood vessel. When a blood clot forms in same area where the blockage occurs, it is known as a thrombus. When a blood clot forms at a distant site and then travels to another part of the body or the brain to block a blood vessel, it is known as an embolus.

Hemorrhagic stroke occurs when a vessel begins to bleed into the brain. This might happen, for example, if an aneurysm bursts or if a small artery ruptures in someone with chronic hypertension. Hemorrhagic stroke can lead to ischemia when blood supply to an area of the brain is disrupted, but it can also result in tissue damage due to blood collecting outside of blood vessels.

In either case, when neurons are deprived of the oxygen and glucose found in blood, mechanisms that are dependent upon energy begin to fail. This can result in a series of biochemical reactions that cause the death of neurons and an area of dead tissue called an infarct, a term that refers to tissue that has died due to a loss of blood supply.

The symptoms of a stroke vary depending on the artery affected and the area of the brain it supplies. Some common symptoms include weakness and loss of sensation on the side of the body opposite where the stroke is occurring---especially in the face and arm, visual impairment, speech difficulties, confusion, loss of balance or coordination, and severe headache.

Reference:

Vanderah TW, Gould DJ. Nolte's The Human Brain. 7th ed. Philadelphia, PA: Elsevier; 2016.