Pulmonary Artery

Structure

The main pulmonary artery is about 5 centimeters long and 3 centimeters wide. It branches into the left and right pulmonary arteries, which divide further into lobar and segmental arteries inside each lung.

Function

This is the only artery in the adult body that carries deoxygenated blood. The pulmonary valve at its origin prevents backflow into the right ventricle.

Pressure

Pressure in the pulmonary circulation is much lower than in the systemic system. Mean pulmonary arterial pressure is roughly 15 mmHg, compared with about 95 mmHg in the aorta.