Great Vessels

There are a number of great vessels associated directly with the heart.  These are the ascending aorta, the pulmonary trunk, the pulmonary veins, the superior vena cava, and the inferior vena cava.

The aorta is the most important artery of the systemic circulation.   Originating from the left ventricle as the ascending aorta, it forms the aortic arch as it curves back over the heart, becoming the descending thoracic aorta as it continues downwards through the thorax, and the descending abdominal aorta as it enters the abdomen.  The aorta gives off branches to all the bodily regions, above the waist, before forming the two common iliac arteries at termination.  The common iliac arteries then supply the lower parts of the body.

The superior vena cava receives deoxygenated blood from all parts of the upper body, while the inferior vena cava receives the venous return from the lower body (including the abdomen).  These two large veins both drain into the right atrium of the heart.

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The pulmonary circulation consists mainly of the pulmonary trunk (which becomes two pulmonary arteries), and the four pulmonary veins.   It also contains pulmonary capillaries, the site of gas exchange in the lungs.  The pulmonary trunk originates in the right ventricle, and receives deoxygenated blood from it.  The pulmonary trunk terminates in the paired pulmonary arteries, the only arteries in the body which carry deoxygenated blood.  The pulmonary arteries carry the blood to the pulmonary capillaries, oxygen and carbon dioxide are exchanged, and the blood is returned to the left atrium via the four pulmonary veins (the only veins in the body to carry oxygenated blood).

 

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