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Encyclopedia > Right coronary artery

The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. The vessels that supply blood high in oxygen to the heart are known as coronary arteries. The vessels that remove the deoxygenated blood from the heart are known as cardiac veins. The arterial system The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. ...


The coronary arteries that run on the surface of the heart are called epicardial coronary arteries. These arteries, when healthy, are capable of autoregulation to maintain coronary blood flow at levels appropriate to the needs of the heart muscle. These relatively narrow vessels are commonly affected by atherosclerosis and can become blocked, causing angina or a heart attack. (See also: circulatory system.) Section of an artery An artery or arterial is also a class of highway. ... Myocardium is the muscular tissue of the heart. ... Angina pectoris (Latin for chest constriction) is the result of a lack of oxygen supply to the heart muscle, due to a reduced blood flow around the hearts blood vessels. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... It has been suggested that Circulation (physiology) be merged into this article or section. ...


The coronary arteries are classified as "end circulation", since they represent the only source of blood supply to the myocardium: there is very little redundant blood supply, which is why blockage of these vessels can be so critical.

Contents


Coronary anatomy

The exact anatomy of the myocardial blood supply varies considerably from person to person. A full evaluation of the coronary arteries requires cardiac catheterization. A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. ...


In general there are two main coronary arteries, the left and right. Both of these arteries originate from the beginning (root) of the aorta, immediately above the aortic valve. As discussed below, the left coronary artery originates from the left aortic sinus, while the right coronary artery originates from the right aortic sinus. The largest artery in the human body, the aorta originates from the left ventricle of the heart and brings oxygenated blood to all parts of the body in the systemic circulation. ... The aortic valve is one of the valves of the heart. ... An aortic sinus is one of the anatomic dilations of the ascending aorta which occurs at the aortic root, i. ...


Left coronary artery

The left coronary artery (LCA) arises from the aorta above the left cusp of the aortic valve as the left main (LM) artery. The left main artery typically runs for 1 to 25 mm and then bifurcates into the left anterior descending (LAD) artery and the left circumflex artery (LCX). If an artery arises from the left main between the LAD and LCX, it is known as the ramus intermedius. The ramus intermedius occurs in 37% of the general population, and is considered a normal variant.


The LAD runs down the anterior interventricular groove. In 78% of cases, it reaches the apex of the heart. It supplies the anterolateral myocardium, apex, and interventricular septum. The LAD typically supplies 45-55% of the left ventricle (LV). The LAD gives off two types of branches: septals and diagonals. Septals originate from the LAD at 90 degrees to the surface of the heart, perforating and supplying the intraventricular septum. Diagonals run along the surface of the heart and supply the lateral wall of the LV and the anterolateral papillary muscle.


The LCX runs across the left atrioventricular groove. It gives off obtuse marginal (OM) branches. The LCX supplies the posterolateral LV and the anterolateral papillary muscle. It also supplies the sinoatrial nodal artery in 38% of people. It supplies 15-25% of the left ventricle in right-dominant systems. If the coronary anatomy is left-dominant, the LCX supplies 40-50% of the left ventricle.


Right coronary artery

The right coronary artery (RCA) originates above the right cusp of the aortic valve. It travels down the right atrioventricular groove, towards the crux of the heart. At the origin of the RCA is the conus artery. In addition to supplying blood to the right ventricle (RV), the RCA supplies 25% to 35% of the left ventricle (LV). In 85% of patients, the RCA gives off the posterior descending artery (PDA). In the other 15% of cases, the PDA is given off by the left circumflex artery. The PDA supplies the inferior wall, ventricular septum, and the posteromedial papillary muscle. The RCA also supplies the SA nodal artery in 60% of patients. 40% of the time, the SA nodal artery is supplied by the LCX.


Coronary artery dominance

The artery that supplies the posterior descending artery and the posterolateral artery (PLA) determines the coronary dominance. If the RCA supplies both these arteries, the circulation can be classified as "right-dominant". If the LCX supplies both these arteries, the circulation can be classified as "left-dominant". If the RCA supplies the PDA and the LCX supplies the PLA, the circulation is known as "co-dominant". Approximately 70% of the general population are right-dominant, 20% are co-dominant, and 10% are left-dominant. [1]


Blood supply of the papillary muscles

The papillary muscles tether the mitral valve (the valve between the left atrium and the left ventricle) and the tricuspid valve (the valve between the right atrium and the right ventricle) to the wall of the heart. If the papillary muscles are not functioning properly, the mitral valve leaks during contraction of the left ventricule. This causes some of the blood to travel "in reverse", from the left ventricle to the left atrium, instead of forward to the aorta and the rest of the body. This leaking of blood to the left atrium is known as mitral regurgitation. In anatomy, the papillary muscles of the heart serve to limit the movements of the mitral and tricuspid valves and prevent them from being everted. ... The mitral valve is a valve in the heart that lies between the left atrium (LA) and the left ventricle (LV). ... This page is about the muscular organ, the Heart. ... In the heart, a ventricle is a chamber which collects blood from an atrium (another heart chamber) and pumps it out of the heart. ... In anatomy, the heart valves are valves in the heart that prevent blood from flowing the wrong way. ... This page is about the muscular organ, the Heart. ... In the heart, a ventricle is a chamber which collects blood from an atrium (another heart chamber) and pumps it out of the heart. ... Mitral regurgitation (MR), also known as mitral insufficiency, is the abnormal leaking of blood through the mitral valve, from the left ventricle into the left atrium of the heart. ...


The anterolateral papillary muscle receives two blood supplies: the LAD and LCX, and is therefore somewhat resistant to coronary ischemia. On the other hand, the posteromedial papillary muscle is supplied only by the PDA. This makes the posteromedial papillary muscle significantly more susceptible to ischemia. The clinical significance of this is that a myocardial infarction involving the PDA is more likely to cause mitral regurgitation. A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ...


Coronary flow

During contraction of the ventricular myocardium (systole), the subendocardial coronary vessels (the vessels that enter the myocardium) are compressed due to the high intraventricular pressures. However the epicardial coronary vessels (the vessels that run along the outer surface of the heart) remain patent. Because of this, blood flow in the subendocardium stops. As a result most myocardial perfusion occurs during heart relaxation (diastole) when the subendocardial coronary vessels are patent and under low pressure. In the heart, a ventricle is a chamber which collects blood from an atrium (another heart chamber) and pumps it out of the heart. ... Systole is the contraction of the chambers of the heart, driving blood out of the chambers. ... Diastole is the period of time when the heart relaxes after contraction. ...


Related topics


  Results from FactBites:
 
Coronary circulation - Wikipedia, the free encyclopedia (1112 words)
The papillary muscles tether the mitral valve (the valve between the left atrium and the left ventricle) and the tricuspid valve (the valve between the right atrium and the right ventricle) to the wall of the heart.
During contraction of the ventricular myocardium (systole), the subendocardial coronary vessels (the vessels that enter the myocardium) are compressed due to the high intraventricular pressures.
In the coronary circulation, norepinephrine elicits vasodilation, due to the predominance of beta-adrenergic receptors in the coronary circulation.
Right coronary artery - Wikipedia, the free encyclopedia (358 words)
The right coronary artery (RCA) originates above the right cusp of the aortic valve.
At the origin of the RCA is the conus artery.
In addition to supplying blood to the right ventricle (RV), the RCA supplies 25% to 35% of the left ventricle (LV).
  More results at FactBites »

 
 

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