The heart supplies the rest of the body with oxygenated blood. This may lead people to wonder how the heart muscle and tissue itself are supplied with oxygenated blood. The answer is simple: The heart gets oxygenated blood from itself. Oxygenated blood from the heart is detoured back to serve the organ that pumps it out.
Coronary Arteries
The aorta, the largest artery in the body, exits the left ventricle of the heart full of oxygenated blood to distribute to the rest of the body. Some of the blood in the aorta makes an almost immediate detour back to the heart via the coronary arteries. The left and right coronary arteries branch off from the aorta right after blood leaves the heart, returning to the heart to supply it with oxygenated blood.
If coronary arteries or the vessels that branch off from them become blocked with plaque or other debris from high cholesterol levels, blood flow to the heart is decreased and a myocardial infarction (heart attack) occurs. Plaque buildup in these vessels is known as coronary artery disease, or CAD, sometimes also called atherosclerosis. CAD is the most common cause of heart disease, the University of Virginia says.
Left Coronary Artery Branches
The left coronary artery divides into the left anterior descending and left circumflex arteries. The left anterior descending artery, often called the LAD, supplies oxygenated blood to the front and bottom of the left ventricle and the front of the septum that divides the heart into two halves, the Cleveland Clinic says. The circumflex artery supplies oxygenated blood to the left atrium and back and front of the left ventricle.
Right Coronary Artery Branches
The right coronary artery supplies blood to the right atrium and ventricle, bottom of the left ventricle and back of the septum. The artery branches into smaller vessels that penetrate the heart muscle, Cardiovascular Consultants says. The smallest blood vessels, the capillaries, are the site of the exchange of oxygen to the cells for waste products that are carried back to the right ventricle of the heart via the coronary veins.
Coronary Veins
The coronary veins return de-oxygenated blood to the right atrium of the heart so it can be pumped from the right ventricle to the lungs to be oxygenated.
Collateral Circulation
Collateral circulation refers to blood vessels that normally don't carry blood. If blockages occur, however, collateral circulation blood vessels open as a detour path around blockages.
