Where are coronary arteries located and what do they do?

Answer 1

The Coronary arteries are the arteries supllying the Heart itself. There are two, a left and a right one. From these arteried other importand arteries such as the Interventricular Artery arise. The supply to the heart is odd in two ways. Firstly all the arteries coming of from the coronary arteries are terminal. This means they do not Anastamoe (join up) with each other at all. This is highle dangerous and evolutionary very unlikly as it increases the chances of a Myocardial Infarction (heart attack) greatly. The reson for this is that if a terminal artery is blocked all the parts that would be supplied by artery below the point of blockage will receive no oxygen (of nutrients for that matter). If there was another artery joined into the end (or even just anywhere below the blockage) as in most organs then any one blockage would make little difference as all the blood could be redirected through the good artery and it would supply everything. The second odd thing about the coronary arteries is that they only suplly the heart during Ventricular Diastole (when the big chambers of the heart are relaxed). This is because they leave the Aorta very early on, infact it is right at rim of Aortic Valve. When the left ventricle contracts it pushes the valve up and open) to let blood inot the aorta. This means the valve "flaps" are pushed right up against the side of the base of the aorta. And if you remember this is where the blood to the coronary arteried goes, so these vessels are blocked by the valve flaps when the heart is pumping. When the ventricle relaxes the flaps fall back down under the pressureof the aortic blood and thus reopen the coronary arteries allowing blood to flow in.