Pulmonary a.

The pulmonary arteries carries deoxygenated blood from the heart to the lungs. They are among the few arteries (other than the umbilical arteries in the fetus) that carry deoxygenated blood.

The pulmonary trunk begins at the base of the right ventricle. It then branches into two pulmonary arteries (left and right), which deliver deoxygenated blood from the right ventricle to the corresponding lung. In the lung, the blood passes through capillaries adjacent to alveoli and becomes oxygenated as part of the process of respiration.

In contrast to the pulmonary arteries, the small bronchial arteries supply oxygenated blood to the lung tissue.

The pulmonary trunk is labeled PT in the dissection image below. It can be found directly inferior to the aortic arch (labeled AA).