Credit: http://library.thinkquest.org/C003758/Structure/coronary.htmAn ongoing irony is happening in the heart. Although it is continuously filled with blood, it provides very little nourishment to its own tissues.
Diffusion is not an option for the delivery of nutrients in the heart because the myocardium is too thick. The system of vessels that provides oxygen rich blood and nutrients to the heart is called the coronary circulation, which is the shortest circulation found in the body. The left and right coronary arteries are the arterial supply of this circulation. The coronary arteries arise from the largest artery in the body, the aorta, and encircle the heart at the coronary sulcus.
Left Coronary ArteryCredit: http://commons.wikimedia.org/wiki/File:Heart_left_lateral_coronaries_diagram.svg
The left coronary artery is concerned with the left side of the heart. The anterior interventricular artery and the circumflex artery are the major branches of the left coronary artery. The anterior interventricular artery which is also called left descending artery follows the path of the anterior interventricular sulcus. It is responsible in order for the blood to reach the interventricular septim and also to the walls of the two ventricles. The circumflex artery is responsible for supplying blood to the left atrium and also brings blood to the posterior walls of the left ventricle.
The RCA or right coronary artery navigates the right side of the heart. The marginal artery and the posterior interventricular artery are the two main branches of the right coronary artery. The marginal artery supply blood to the heart muscles on the lateral right side of the heart. The posterior interventricular artery is connected to the apex of the heart and provides blood to the posterior walls of right side of the heart. Almost all the right ventricle and the right atrium are being supplied by the right coronary artery.
The Blood SupplyCredit: http://topnews.net.nz/content/21775-blood-supply-falls-drastically-across-southeast
The coronary arteries supply intermittent flow of blood to the heart muscles. Together with their branches, the coronary arteries are located within the epicardium and gives nourishment inwards to the myocardium. These arteries supply blood during the relaxation phase of the blood. They are unable to deliver blood during contraction because they are compressed during that time. The heart is a fairly small organ, which roughly has 1/200 of the weight of the body but surprisingly needs close to 1/20 of the blood supply of the body to sustain its function. The left ventricle, having the greatest number of heart muscle, receives the majority of the blood supplied by the coronary arteries.
After delivering the nutrients and oxygenated blood to the heart muscles, the cardiac veins then collects the deoxygenated blood. The cardiac veins traverse the same path that the coronary artery travels and it delivers the collected blood directly to the right atrium. The coronary veins then anastomosed to form the coronary sinus. The great cardiac vein, the middle cardiac vein and the small cardiac vein are the three tributaries of the coronary sinus. Blockage of the coronary artery is a serious and sometimes fatal situation.