Anatomy, Thorax, Heart Pulmonary Arteries

The main pulmonary artery and the subsequent right and left pulmonary arteries sit within the middle mediastinum. They arise from the right ventricle of the four-chambered heart and transport blood to the lungs. De-oxygenated blood from the body's somatic cells travels to the right atrium, then into the right ventricle, and through the main pulmonary artery and its branches before blood enters the lungs for oxygenation and gas exchange. These steps are all prerequisites for normal human physiologic function.