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Coronary Arteries and Heart Function

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Topic Overview

The coronary arteries deliver blood to the heart muscle, providing a continuous supply of oxygen and nutrients needed for it to stay healthy and function normally.

Supply and demand

The coronary arteries regulate the supply of blood to your heart muscle depending on how much oxygen your heart needs at the time, as indicated by:

  • The number of times your heart beats per minute (heart rate).
  • Your blood pressure.
  • The force of your heart's contractions.
  • The thickness of your heart muscle.

The harder the heart has to work to pump blood, the more oxygen it needs. For example, when you exercise, your heart rate and blood pressure increase, which in turn increases your heart's demand for oxygen.

The main way to increase the oxygen supply to the heart is to increase the blood flow through the coronary arteries. Your heart increases the blood flow by widening (dilating) your coronary arteries.

If your coronary arteries aren't able to dilate properly, your heart muscle may not be able to get the amount of oxygen it needs to function properly.

Anatomy of the coronary arteries

Your left ventricle pumps blood into the main artery of your body, called the aorta. See a picture of the heart and coronary arteries camera.gif. Close to the heart, the two main coronary arteries branch off of your aorta.

  • The left main coronary artery is a short vessel that branches into the:
    • Left anterior descending artery, which supplies blood to the front (anterior wall) and part of the side (anterolateral wall) of the left ventricle, to the top of the left ventricle, and to most of the wall between the ventricles (interventricular septum).
    • Circumflex artery, which passes behind the heart between the left atrium and left ventricle and supplies blood to the side (lateral wall) of the left ventricle. In a small number of people, the circumflex artery supplies the lower and back portions of the left ventricle.
  • The right coronary artery supplies blood to the right ventricle and then supplies the underside (inferior wall) and backside (posterior wall) of the left ventricle.
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WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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