How Does a Stroke Happen?

What is a Stroke?

A stroke is a malfunction of the brain when blood supply to the brain is either cut off, or extensive internal bleeding in the cranial region does not allow enough blood to reach the brain. Strokes can be deadly, and even when they do not kill their victim, they can cause long-term brain damage. A stroke cuts off the oxygen supply to the brain. Without oxygen, your brain cells slowly begin to weaken and die. Approximately 70,000 Americans experience a stroke every year (WebMD Statistic).

Types of Strokes

There are three different types of strokes. The hemorrhagic stroke is due to internal bleeding in the brain, the thrombus stroke is caused by a blood clot that has formed inside the brain, and the embolus stroke is caused by a blood clot that has traveled from another area of the body and gotten stuck in the brain.

Narrowing

The first way that a stroke can happen is through the narrowing of the arteries. Your arteries act as a transportation system throughout your body. One of the main life-giving elements that your arteries transport is oxygen. When your arteries become to narrow, they can block blood from being transported to the brain. Once this happens oxygen is no longer able to reach the brain, causing a stroke.

Bleeding

Another way a stroke can happen is if an artery in or surrounding the brain bursts. This is usually caused by an increase in internal artery pressure either from high blood pressure or a birth defect in the artery. Once the artery bursts it causes massive internal bleeding, damaging the brain tissues around the broken artery.

Clotting

Clotting is one of the most common causes of a stroke. This type of stroke can be either thrombus or embolus, depending on where the blood clot decides to form. Regardless of where the blood clot forms in the body, at any time it can be lodged loose by the natural blood flow of the body and pushed along in the bloodstream. Arteries near the brain are much smaller than many of the other arteries in the body, causing the clot to get stuck in the cranial cavity. This causes blood to be unable to reach specific parts of the brain, causing a stroke. Blood clots can also travel to the heart, causing a heart attack.

Tumor

The final reason a stroke may happen is through a tumor or other swelling in the brain caused by infection. Once the tumor or swelling grows, it can cause pressure to be applied to the surrounding arteries. So much pressure can be applied, especially with tumor growth, that the artery can be completely clamped off. This keeps blood from being able to reach whatever area of the brain that artery feeds.

Resources

• Additional Information on Strokes