Aluminum Grades Series 7xxx. Zinc, in amounts of 1 to 8% is the major alloying element in 7xxx series aluminum alloys (7075, 7050, 7049, 710.0; 711.0 etc.), and when coupled with a smaller percentage of magnesium results in heat-treatable alloys of moderate to very high strength.
We previously learned that arteries carry blood away from the heart and that veins carry blood toward the heart. This idea holds true here because we see that the pulmonary arteries are carrying blood away from the heart and the pulmonary veins are carrying blood to the heart. The interesting thing is that in most areas of the body, veins carry blood that is low in oxygen and arteries usually carry blood that's rich in oxygen.
These two arteries branch into other arteries, including the circumflex artery, that also supply blood to the heart. The cardiac veins collect blood from the heart muscle and empty it into a large vein on the back surface of the heart called the coronary sinus, which returns the blood to the right atrium.lood Supply of the Heart. Like all organs, the heart needs a constant supply of oxygen-rich blood. A system of arteries and veins, called the coronary circulation, supplies the heart muscle (myocardium) with oxygen-rich blood and then returns oxygen-depleted blood to the right atrium.