Yes, the wall of the pulmonary artery contains a layer of smooth muscle to deal with the high pressure from the heart, and to help push the blood along.
Yes! It is the only artery that carries deoxygenated blood (other than umbilical arteries in the fetus), it is located close to the heart, where large (conducting) arteries don't have smooth muscles...
It is called a artery because arteries are vessels that stem from the heart and deliver blood to the organs. The pulmonary artery is still an artery, even though it carries deoxygenated blood,...