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What is atherosclerosis?

Atherosclerosis is a disease in which cholesterol builds up in the walls of arteries. Arteries are flexible tubes that carry oxygen-rich blood to all of your body.

Atherosclerosis is a disease in which cholesterol builds up in the walls of arteries. Arteries are flexible tubes that carry oxygen-rich blood to all of your body. Every artery has a wall, an inner lining and an open space in the middle. The heart pumps blood through the artery like water flowing through a pipe. Cholesterol, a kind of fat, travels in the blood. See the yellow specks in the blood? Those are little particles of fat. Atherosclerosis begins when something injures the inner lining of the artery. There are many possible causes of injury. High blood pressure is one, so is smoking, infection may be another. The injury makes it easier for cholesterol to burrow under the artery's inner lining. The streak of yellow cholesterol in the lining of the artery is called a fatty streak. The more cholesterol in the blood, the more likely that fatty streaks will form. In people who eat high fat diets, fatty streaks may form as early as age 20. When cholesterol gets into the wall of an artery, the wall becomes inflamed. The inflammation turns the fatty streak into a cholesterol-filled plaque. The plaque pushes into the wall of the artery. The inside of the plaque contains a pool of cholesterol that keeps growing. Now, see this? This is a fibrous cap that grows over the top of the plaque. The cap holds the cholesterol inside the plaque. So far, this plaque hasn't affected the flow of blood through the artery but, over time, that can change. The plaque can continue to grow invading the space in the middle of the artery and slowing the flow of blood. When atherosclerosis affects the coronary arteries, it can interfere with blood flow to the heart. Some people have atherosclerosis of the coronary arteries but don't know it because it isn't bad enough to cause symptoms. Other people develop chest pain called angina and some have a heart attack. To learn more about these conditions, see the videos, "What is Angina?" and "What is a Heart Attack?" From Harvard, I wish you good health.

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