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Encyclopedia > Coronary circulation
Coronary circulation
An anterior view of the heart shows the right coronary artery and the anterior descending branch of the left coronary artery.
Base and diaphragmatic surface of heart.
MeSH Coronary+Vessels

The coronary circulation consists of the blood vessels that supply blood to and from the heart muscle itself. Although blood fills the chambers of the heart, the muscle tissue of the heart, or myocardium, is so thick that it requires coronary blood vessels to deliver blood deep into the myocardium. The vessels that supply blood high in oxygen to the myocardium are known as coronary arteries. The vessels that remove the deoxygenated blood from the heart muscle are known as cardiac veins. Image File history File links Gray492. ... The heart and lungs, from an older edition of Grays Anatomy. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... The left coronary artery, also abbreviated LCA, arises from the aorta above the left cusp of the aortic valve. ... Image File history File links Gray491. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... f you all The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... The heart and lungs, from an older edition of Grays Anatomy. ... Myocardium is the muscular tissue of the heart. ...


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 For other uses, see Artery (disambiguation). ... Myocardium is the muscular tissue of the heart. ... The latin word angina refers to a painful constriction or tightness somewhere in the body. ... Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... Diagram of the human circulatory system. ...


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

Schematic view of the heart vessels
Schematic view of the heart vessels
The coronary arteries' ostia and their proximal segments. The proximal portion of right coronary artery and its ostium can be seen at the lower left (of the image). The left main coronary artery and its ostium are seen on the right (of the image). An aortic valve that, due to rheumatic heart disease, has a severe stenosis is seen at the centre (of the image). The pulmonary trunk is seen at the lower right (of the image). Autopsy specimen.
The coronary arteries' ostia and their proximal segments. The proximal portion of right coronary artery and its ostium can be seen at the lower left (of the image). The left main coronary artery and its ostium are seen on the right (of the image). An aortic valve that, due to rheumatic heart disease, has a severe stenosis is seen at the centre (of the image). The pulmonary trunk is seen at the lower right (of the image). Autopsy specimen.

The exact anatomy of the myocardial blood supply varies considerably from person to person. A full evaluation of the coronary arteries requires cardiac catheterization or CT coronary angiography. Image File history File links Download high-resolution version (960x1440, 73 KB) Cardiac vessels File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Coronary circulation Right coronary artery Small cardiac vein Middle cardiac vein Posterior interventricular artery Right marginal... Image File history File links Download high-resolution version (960x1440, 73 KB) Cardiac vessels File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Coronary circulation Right coronary artery Small cardiac vein Middle cardiac vein Posterior interventricular artery Right marginal... Image File history File links Aortic_stenosis_rheumatic,_gross_pathology_20G0014_lores. ... Image File history File links Aortic_stenosis_rheumatic,_gross_pathology_20G0014_lores. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... The left coronary artery, abbreviated LCA and also known as the left main coronary artery (often abbreviated LMCA), arises from the aorta above the left cusp of the aortic valve. ... The aortic valve is one of the valves of the heart. ... Rheumatic fever is an inflammatory disease which may develop after an infection with streptococcus bacteria (such as strep throat or scarlet fever) and can involve the heart, joints, skin, and brain. ... Aortic valve stenosis (AS) is a heart condition caused by the incomplete opening of the aortic valve. ... The pulmonary arteries carry blood from the heart to the lungs. ... Post-mortem, postmortem and post mortem redirect here. ... Cardiac catheterization (heart cath) is the insertion of a catheter into a chamber or vessel of the heart. ... This article does not cite its references or sources. ...


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 coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... The left coronary artery, also abbreviated LCA, arises from the aorta above the left cusp of the aortic valve. ... The aorta (generally pronounced or ay-orta) is the largest artery in the human body, originating from the left ventricle of the heart and bringing 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. ...


Variations

Four percent of people have a third, the posterior coronary artery. In rare cases, a patient will have one coronary artery that runs around the root of the aorta.


Occasionally, a coronary artery will exist as a double structure (ie there are two arteries, parallel to each other, where ordinarily there is one). Tark Medesco has this variation, which led to a mishap during his CABG operation. A coronary artery bypass graft (CABG) or heart bypass is a surgical procedure performed in patients with coronary artery disease (see atherosclerosis) for the relief of angina and possible improved heart muscle function. ...


Coronary artery dominance

The artery that supplies the posterior descending artery (PDA) and the posterolateral artery (PLA) determines the coronary dominance. The Right coronary artery passes at first between the conus arteriosus and the right auricula and then runs in the right portion of the coronary sulcus, coursing at first from the left to right and then on the diaphragmatic surface of the heart from right to left as far as...

  • If the right coronary artery (RCA) supplies both these arteries, the circulation can be classified as "right-dominant".
  • If the left circumflex artery (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. The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... The LCX, or left circumflex artery (or circumflex artery, or circumflex branch of the left coronary artery) follows the left part of the coronary sulcus, running first to the left and then to the right, reaching nearly as far as the posterior longitudinal sulcus. ...


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 ventricle. 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. ... The mitral valve, also known as the bicuspid valve, is a valve in the heart that lies between the left atrium (LA) and the left ventricle (LV). ... Anterior (frontal) view of the opened 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. ... The right ventricle is one of four chambers (two atria and two ventricles) in the human 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. In medicine, ischemia (Greek ισχαιμία, isch- is restriction, hema or haema is blood) is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. ... Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ...


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. This contributes to the filling difficulties of the coronary arteries. In the heart, a ventricle is a heart chamber which collects blood from an atrium (another heart chamber that is smaller than a ventricle) and pumps it out of the heart. ... Systole can mean the following: Systole (medicine) is a term describing the contraction of the heart. ... Diastole is the period of time when the heart relaxes after contraction. ...


The primary determinant of coronary blood flow is the level of myocardial/cardiac oxygen consumption. As the heart beats more vigorously, ATP is consumed at a greater rate due to the increased force and/or frequency of contraction and the depolarization and repolarization of the cardiac membrane potential. The increase in oxygen consumption results in the release of a vasodilator substance, the identity of which remains unknown. The vasodilator reduces vascular resistance and allows more blood to flow through the heart during each diastole. Systolic compression remains the same. Failure of oxygen delivery via increases in blood flow to meet the increased oxygen demand of the heart results in tissue ischemia, a condition of oxygen debt. Brief ischemia is associated with intense chest pain, known as angina. Severe ischemia can cause the heart muscle to die of oxygen starvation, called a myocardial infarction. Chronic moderate ischemia causes contraction of the heart to weaken, known as myocardial hibernation. Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... This article or section is in need of attention from an expert on the subject. ... Vasodilation is where blood vessels in the body become wider following the relaxation of the smooth muscle in the vessel wall. ... The latin word angina refers to a painful constriction or tightness somewhere in the body. ... Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ...


In addition to metabolism, the coronary circulation possesses unique pharmacologic characteristics. Prominent among these is its reactivity to adrenergic stimulation. The majority of vasculature in the body constricts to norepinephrine, a sympathetic neurotransmitter the body uses to increase blood pressure. In the coronary circulation, norepinephrine elicits vasodilation, due to the predominance of beta-adrenergic receptors in the coronary circulation. Agonists of alpha-receptors, such as phenylephrine, elicit very little constriction in the coronary circulation. Norepinephrine (INN) or noradrenaline (BAN) is a catecholamine and a phenethylamine with chemical formula C8H11NO3. ... Norepinephrine (INN) or noradrenaline (BAN) is a catecholamine and a phenethylamine with chemical formula C8H11NO3. ...


See also

Coronary artery anomalies are congenital abnormalities in the coronary anatomy of the heart. ... The heart and lungs, from an older edition of Grays Anatomy. ... Myocardium is the muscular tissue of the heart. ... In anatomy, the papillary muscles of the heart serve to limit the movements of the mitral and tricuspid valves. ... Early in a coronary artery bypass surgery during vein harvesting from the legs (left of image) and the establishment of bypass (placement of the aortic cannula) (bottom of image). ...

References


  Results from FactBites:
 
Coronary catheterization - Wikipedia, the free encyclopedia (1750 words)
A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter.
The first case of coronary catheterization was serendipitous: Sones, a pediatric cardiologist at the Cleveland Clinic, accidentally injected radiocontrast in the coronary artery instead of the left ventricle.
During coronary catheterization (often referred to as a cath by physicians), blood pressures are recorded and X-Ray motion picture shadow-grams of the blood inside the coronary arteries are recorded.
  More results at FactBites »


 

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