BLOOD VESSELS OF THE PULMONARY CIRCULATION
describe the blood vessels of the pulmonary circulation.
The pulmonary circulation is the system of blood vessels that carries blood from the right ventricle of the heart to the lungs and back to the left atrium of the heart. Blood from the right ventricle is pumped into a short vessel called the pulmonary (pŭl′ mō-nār-ē)trunk (figure 13.5). The pulmonary trunk then branches into the right and left pulmonary arteries, which extend to the right andleft lungs, respectively. These arteries carry oxygen-poor blood tothe pulmonary capillaries in the lungs, where the blood takes up O2 and releases CO2. Blood rich in O2 flows from the lungs to the left atrium. Four pulmonary veins (two from each lung) exit the lungs and carry the oxygen-rich blood to the left atrium. Figure 13.5 traces the path of the pulmonary circulation and shows it in rela-tion to the systemic circulation, described next.