| Coronary arteries | |
|---|---|
 Coronary arteries (labeled in red text) and other major landmarks (in blue text) | |
| Identifiers | |
| FMA | 49893 |
| Anatomical terminology | |
Thecoronary arteries are thearterial blood vessels ofcoronary circulation, which transportoxygenated blood to theheart muscle. Theheart requires a continuous supply of oxygen to function and survive, much like any other tissue or organ of the body.[1]
The coronary arteries wrap around the entire heart. The two main branches are theleft coronary artery andright coronary artery. The arteries can additionally be categorized based on the area of the heart for which they provide circulation. These categories are calledepicardial (above theepicardium, or the outermost tissue of the heart) andmicrovascular (close to theendocardium, or the innermost tissue of the heart).[2]
Reduced function of the coronary arteries can lead to decreased flow of oxygen and nutrients to the heart. Not only does this affect supply to the heart muscle itself, but it also can affect the ability of the heart to pump blood throughout the body. Therefore, any disorder or disease of the coronary arteries can have a serious impact on health, possibly leading toangina, aheart attack, and even death.[3]
The coronary arteries are mainly composed of the left and right coronary arteries, both of which give off several branches, as shown in the 'coronary artery flow' figure.
Theleft coronary artery arises from theaorta within the left cusp of theaortic valve and feeds blood to the left side of theheart. It branches into two arteries, theleft anterior descending and theleft circumflex. The left anterior descending artery perfuses theinterventricular septum and anterior wall of theleft ventricle. The left circumflex artery perfuses the left ventricular free wall. In approximately 33% of individuals, the left coronary artery gives rise to theposterior descending artery[4] which perfuses the posterior and inferior walls of the left ventricle. Sometimes a third branch is formed at the fork between left anterior descending and left circumflex arteries, known as aramus orintermediate artery.[5]
Theright coronary artery (RCA) originates within the right cusp of the aortic valve. It travels down the rightcoronary sulcus, towards thecrux of the heart. The RCA primarily branches into theright marginal arteries, and, in 67% of individuals, gives place to the posterior descending artery.[4] The right marginal arteries perfuse the right ventricle and the posterior descending artery perfuses the left ventricular posterior and inferior walls.
There is also theconus artery, which is only present in about 45 percent of the human population, and which provides collateral blood flow to the heart when the left anterior descending artery is occluded.[6][7]
Narrowing of the arteries can be caused by a process known asatherosclerosis (most common),arteriosclerosis, orarteriolosclerosis. This occurs whenplaques (made up of deposits ofcholesterol and other substances) build up over time in the walls of the arteries.Coronary artery disease (CAD) or ischemic heart disease are the terms used to describe narrowing of the coronary arteries.[8]
As the disease progresses, plaque buildup can partially block blood flow to the heart muscle. Without enough blood supply (ischemia), the heart is unable to work properly, especially under increased stress.Stable angina is chest pain on exertion that improves with rest.Unstable angina is chest pain that can occur at rest, feels more severe, and/or last longer than stable angina. It is caused by more severe narrowing of the arteries.[9]
Aheart attack results from a sudden plaque rupture and formation of athrombus (blood clot) that completely blocks blood flow to a portion of the heart, leading to tissue death (infarct).
CAD can also result inheart failure orarrhythmias. Heart failure is caused by chronic oxygen deprivation due to reduced blood flow, which weakens the heart over time. Arrhythmias are caused by inadequate blood supply to the heart that interferes with the heart's electric impulse.
The coronary arteries can constrict as a response to various stimuli, mostly chemical. This is known as acoronary reflex.
There is also a rare condition known asspontaneous coronary artery dissection, in which the wall of one of the coronary arteries tears, causing severe pain.[10] Unlike CAD, spontaneous coronary artery dissection is not due to plaque buildup in arteries, and tends to occur in younger individuals, including women who have recently given birth or men who do intense exercise.[11]
Coronary artery dominance is described as the coronary artery that give branches to supply the right posterior descending artery and supplies the inferior wall of the heart. In 80 to 85% of the population, the right coronary artery supplies the posterior descending artery, making it right heart dominant while in 7 to 13% of the population, the left coronary artery supplies the posterior descending artery, making it left heart dominant. In 7 to 8% of the population, both right and left coronary arteries supplies the posterior descending artery, making it right and left co-dominance. Narrowing of coronary arteries is more frequent in those who are left dominant when compared to those who have right dominant or co-dominant hearts.[12]
The wordcorona is aLatin word that means "crown", from theAncient Greekκορώνη (korōnè, "garland, wreath"). It was applied to the coronary arteries because of a notional resemblance (compare the photos).
The wordarterie in Anglo-French (artaire inOld French, andartērium in Latin) means "windpipe" and "an artery". It was applied to the coronary arteries because the arteries do not contain blood after death.
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