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. 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.
What are collateral coronary arteries?
The coronary arteries also include the collateral coronary
arteries, small blood vessels that connect the normal coronary arteries with
one another. When the heart is healthy, these vessels play only a minor role.
When a coronary artery becomes obstructed, though, collateral coronary
arteries help increase the flow of blood to the area of the heart that is being
deprived of blood flow. These vessels, although small, may actually succeed in
providing sufficient blood to help prevent major damage to the heart muscle
during a heart attack.
Why are my coronary arteries so important?
When the heart doesn't get enough oxygen-rich blood through the
coronary arteries, the affected heart muscle can weaken or die. This is what
happens during a heart attack. The damaged heart muscle cannot pump
effectively, leading to heart failure.
