Yellow - wall of the aorta (cut)
Green - aortic valve
Red - opening to coronary artery
Small Black outline - cusp of semilunar valve as it would appear with valve closed.
Explanation - The first arteries to exit the aorta are the left and right coronary arteries.
When the aortic valve opens and the blood is ejected from the left ventricle the flattened cusps of the valves cover up
the openings to the coronary arteries thus momentarily interrupting the flow of blood to the heart muscle (myocardium).