The course of the aorta
The initial part of the aorta, the ascending aorta, rises out of the left ventricle, which it is separated by the aortic valve. The two coronary arteries of the heart come out of this part of the aorta.
The aorta then arches back, over the right pulmonary artery. Three vessels come out of the aortic arch, the brachiocephalic artery, the left common carotid artery, and the left subclavian artery. These vessels supply blood to the head and the arms.
As it travels down the posterior wall of the abdomen, the abdominal aorta runs on the left of the inferior vena cava, giving off major blood vessels to the gut organs and kidneys. There are many recognized variants in the vasculature of the gastrointestinal system. The most common arrangement is for the aorta to give off the celiac trunk, the superior mesenteric artery and the inferior mesenteric artery in turn. The renal arteries usually branch from the abdominal aorta in between the celiac trunk and the superior mesenteric artery.
The aorta terminates by dividing into two branches, the left and right iliac arteries that branch to supply the lower limbs and the pelvis.
The aorta is an elastic artery, and as such is quite distensible. When the left ventricle contracts to force blood into the aorta, the aorta stretches out. This stretching gives the potential energy that will help maintain blood pressure during diastole, as during this time the aorta contracts passively.