The coronary arteries deliver blood to the heart muscle and regulate the supply of blood to the heart. The coronary arteries are found along the outside of the heart with small branches that go into the heart muscle to supply it with blood.
The two main coronary arteries are the left main and right coronary arteries. The left main coronary artery delivers blood to the left side of the heart muscle, which includes the left ventricle and left atrium. The left main coronary artery is comprised of the left anterior descending artery branch, which supplies blood to the front part of the left side of the heart muscle, and the circumflex artery, which supplies blood to the heart's outer side and back. The right coronary artery delivers blood to the right ventricle, right atrium and the sinoatrial and atrioventricular nodes. These maintain the heart's rhythm.
Because the heart needs oxygen-rich blood to function properly, the heart must increase the blood flow through the coronary arteries to increase the oxygen supply. The heart dilates the coronary arteries to increase the blood flow. A coronary disorder or disease can result in reduced flow of oxygen and nutrients to the heart muscle. The most common cause of heart disease is atherosclerosis, the accumulation of plaque in a coronary artery that can cause it to become blocked.