The Aorta is ARTERY that carries BLOOD from the HEART to the body. 1  The largest blood vessel in the body, the aorta arises from the left ventricle. At its widest point the aorta is about one and a half inches in diameter. As the aorta leaves the heart it ascends to curve behind the right atrium. The first arteries to branch from the base of the ascending aorta are the right and left CORONARY ARTERIES that supply the heart MUSCLE with blood. Branching from the arch as the aorta crests over the heart are the three arteries that carry blood to the upper body: