They originate at the base of the aorta, commonly known as the aortic root.
The RCA supplies the right ventricular wall, the posterior part of the interventricular septum, and most of the inferior wall of the left ventricle.
In about 50% of people, the right coronary artery also supplies the area of the right atrium near the orifice of the superior vena cava where the sinoatrial node, the pacemaker of the heart, is located.
In the healthy heart, the coronary arteries can meet this increased demand by dilating and increasing coronary blood flow, thus providing more oxygen to the myocardium.
When coronary artery disease decreases the elasticity or obstructs flow through a coronary artery, the blood supply to the area served by the artery is threatened.
Virtually all the blood from the left coronary artery drains through the coronary veins, through the coronary sinus, and into the right atrium.
The blood from the right coronary artery drains mainly into the anterior cardiac veins and into the right atrium.
In the capillaries, oxygen- and nutrient-rich blood is delivered to the myocardium while carbon dioxide and other waste products are removed.
Blood then flows into small venules and veins leading to larger venous channels.
Similar to arteries elsewhere in the body, the coronary arteries branch into small arteries and arterioles.
These vessels terminate in end arteries that supply the myocardial tissue with blood.
The Left Coronary Artery arises from the aortic root as a single short main left coronary artery, the left mainstem.