The coronary arteries are the arterial blood vessels of

coronary circulation Coronary circulation is the circulation of blood in the blood vessels that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle. Cardiac veins then drain away the blood after it has been deoxygenat ...

, which transport oxygenated blood to the

heart muscle Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate Muscle tissue, muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striat ...

. The

heart The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon diox ...

requires a continuous supply of oxygen to function and survive, much like any other tissue or organ of the body. The coronary arteries wrap around the entire heart. The two main branches are the left coronary artery and

right coronary artery In the blood supply of the heart, the right coronary artery (RCA) is an artery originating above the right cusp of the aortic valve, at the right aortic sinus in the heart. It travels down the right coronary sulcus, towards the crux of the he ...

. The arteries can additionally be categorized based on the area of the heart for which they provide circulation. These categories are called ''epicardial'' (above the

epicardium The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made of ...

, or the outermost tissue of the heart) and ''microvascular'' (close to the

endocardium The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the endothelial cells that line blood vessels. The endocardium also provides protection to the v ...

, or the innermost tissue of the heart). 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 to

angina Angina, also known as angina pectoris, is chest pain or pressure, usually caused by insufficient blood flow to the heart muscle (myocardium). It is most commonly a symptom of coronary artery disease. Angina is typically the result of obstruc ...

, a

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which m ...

, and even death.

Structure

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. * Coronary arteries flow

Aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

** Left coronary artery ***

Left anterior descending artery The left anterior descending artery (also LAD, anterior interventricular branch of left coronary artery, or anterior descending branch) is a branch of the left coronary artery. Blockage of this artery is often called the ''widow-maker infarction' ...

*** Left circumflex artery *** Posterior descending artery ***Ramus or intermediate artery **

Right coronary artery In the blood supply of the heart, the right coronary artery (RCA) is an artery originating above the right cusp of the aortic valve, at the right aortic sinus in the heart. It travels down the right coronary sulcus, towards the crux of the he ...

*** Right marginal artery *** Posterior descending artery The left coronary artery arises from the

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

within the left cusp of the

aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. Th ...

and feeds blood to the left side of the

. It branches into two arteries, the

left anterior descending The left anterior descending artery (also LAD, anterior interventricular branch of left coronary artery, or anterior descending branch) is a branch of the left coronary artery. Blockage of this artery is often called the ''widow-maker infarction' ...

and the left circumflex. The left anterior descending artery perfuses the

interventricular septum The interventricular septum (IVS, or ventricular septum, or during development septum inferius) is the stout wall separating the ventricles, the lower chambers of the heart, from one another. The ventricular septum is directed obliquely backwar ...

and anterior wall of the

left ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper ...

. The left circumflex artery perfuses the left ventricular free wall. In approximately 33% of individuals, the left coronary artery gives rise to the posterior descending artery 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 a ''ramus'' or ''intermediate artery''. The

(RCA) originates within the right cusp of the aortic valve. It travels down the right coronary sulcus, towards the crux of the heart. The RCA primarily branches into the right marginal arteries, and, in 67% of individuals, gives place to the posterior descending artery. The right marginal arteries perfuse the right ventricle and the posterior descending artery perfuses the left ventricular posterior and inferior walls. There is also the conus 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.

Clinical significance

Narrowing of the arteries can be caused by a process known as

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually ...

(most common),

arteriosclerosis Arteriosclerosis is the thickening, hardening, and loss of elasticity of the walls of arteries. This process gradually restricts the blood flow to one's organs and tissues and can lead to severe health risks brought on by atherosclerosis, which ...

, or

arteriolosclerosis Arteriolosclerosis is a form of cardiovascular disease involving hardening and loss of elasticity of arterioles or small arteries and is most often associated with hypertension and diabetes mellitus. Types include hyaline arteriolosclerosis and hy ...

. This occurs when

plaques Plaque may refer to: Commemorations or awards * Commemorative plaque, a plate or tablet fixed to a wall to mark an event, person, etc. * Memorial Plaque (medallion), issued to next-of-kin of dead British military personnel after World War I * Pla ...

(made up of deposits of

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membr ...

and other substances) build up over time in the walls of the arteries.

Coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves Ischemia, the reduction of blood flow to the myocardium, heart muscle due to build-up o ...

(CAD) or ischemic heart disease are the terms used to describe narrowing of the coronary arteries. As the disease progresses, plaque buildup can partially block blood flow to the heart muscle. Without enough blood supply (

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

), the heart is unable to work properly, especially under increased stress. Stable angina is chest pain on exertion that improves with rest.

Unstable angina Unstable angina (UA), also called crescendo angina, is a type of angina pectoris that is irregular. It is also classified as a type of acute coronary syndrome (ACS). It can be difficult to distinguish unstable angina from non-ST elevation (non-Q ...

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. Heart attack-NIH

results from a sudden plaque rupture and formation of a

thrombus A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cr ...

(blood clot) that completely blocks blood flow to a portion of the heart, leading to tissue death ( infarct). CAD can also result in

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

arrhythmias Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...

. 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 a coronary reflex. There is also a rare condition known as

spontaneous coronary artery dissection Spontaneous coronary artery dissection (SCAD) is an uncommon but potentially lethal condition in which one of the arteries that supply the heart spontaneously develops a blood collection, or hematoma, within the artery wall. This leads to a separ ...

, in which the wall of one of the coronary arteries tears, causing severe pain. 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. 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.

Name etymology

The word ' is a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

word meaning "crown", from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

(, “garland, wreath”). It was applied to the coronary arteries because of a notional resemblance (compare the photos). The word ''arterie'' in Anglo-French (' in

Old French Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intelligi ...

, and ' in Latin) means "windpipe" and "an artery." It was applied to the coronary arteries because the arteries do not contain blood after death.

Additional images

References

{{Authority control Anatomy Cardiac anatomy

Structure

Clinical significance

Name etymology

See also

Additional images

References