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Flashcards in Coronary arteries Deck (16)
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Which two of the three layers of the heart do the coronary arteries supply?

Epicardium & myocardium


Where do the coronary arteries arise from?

The right and left aortic sinuses of the ascending aorta just above the aortic valve


Where does the left coronary artery lie?

In the left atrioventricular groove between the pulmonary trunk and left auricle.


What does the left anterior descending artery run along?

Anterior interventricular septum


Where does the circumflex artery originate from and where does it run?

Left coronary artery
Runs laterally & onto the posterior surface of the heart


Where does the right coronary artery lie?

In the coronary/right atrioventricular groove


What is the coronary sinus?

A short venous conduit which receives the deoxygenated blood from the cardiac vessels


Where does the coronary sinus drain into?

Right atrium


What does the right coronary artery become when it reaches the posterior surface of the heart?

Right posterior atrioventricular artery and then the posterior interventricular artery


What are the two most common sites of narrowing/occlusion within the coronary arteries?

LAD or right coronary artery


What coronary artery supplies the SA node?

SA nodal branch of the RCA


What coronary artery supplies the AV node?

AV nodal branch of the RCA, near the origin of the posterior interventricular artery


Which coronary artery supplies the interventricular septum?

Left anterior descending


What is the significance of the high oxygen extraction of the heart under resting conditions?

Myocardial oxygen perfusion cannot be increased by increasing the oxygen extraction - can only be increased by increasing coronary blood flow


What are the intrinsic mechanisms of coronary blood flow?

Decreased Po2 causes vasodilatation of the coronary arterioles
Metabolic hyperaemia matches flow to demand
Adenosine (from ATP) is a potent vasodilator


What are the extrinsic mechanisms of coronary blood flow?

Coronary arterioles supplied by sympathetic vasoconstrictor nerves, but:
Over-ridden by metabolic hyperaemia as a result of increased heart rate and stroke volume
So sympathetic stimulation of the heart results in coronary vasodilatation despite direct vasoconstrictor effect (functional sympatholysis)
Circulating adrenaline activates beta 2 adrenergic receptors, which cause vasodilatation