Coronary arteries

The coronary arteries are the arteries of the coronary circulation, which transports blood into and out of the cardiac muscle. They are mainly composed of the left and right coronary arteries, both of which give off branches. Coronary arteries can also be categorized as epicardial (above the epicardium) and microvascular (close to the endocardium). Cast of coronary arteries. Right - yellow, left - red The coronary arteries are the arteries of the coronary circulation, which transports blood into and out of the cardiac muscle. They are mainly composed of the left and right coronary arteries, both of which give off branches. Coronary arteries can also be categorized as epicardial (above the epicardium) and microvascular (close to the endocardium). The left coronary artery arises from the aorta above the left cusp of the aortic valve and feeds blood to the left side of the heart. It branches into two arteries and sometimes a third branch is formed at the fork, known as a ramus or intermediate artery. The right coronary artery originates from above the right cusp of the aortic valve. It travels down the right coronary sulcus, towards the crux of the heart. There is also the conus artery, which is only present in about 45 per cent of the human population, and which may provide collateral blood flow to the heart when the left anterior descending artery is occluded. Either or both arteriosclerosis and atherosclerosis, can cause one or more of the coronary arteries or their branches to become seriously blocked, leading to angina, heart attack, or both. Percutaneous coronary interventions (such as balloon angioplasty) or coronary artery bypass surgery can be performed to decrease or bypass the blockages (respectively). 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. The word corona is a Latin word meaning 'crown', from the Ancient Greek κορώνη (korōnè, “garland, wreath”). It was applied to the coronary arteries because of a notional resemblance (compare the photos).