Despite the many differences, the aorta and the pulmonary artery share a lot of similarities among them as well. Some of their similarities include:Both of them are vital arteries in the human body.Both of them form an essential part of the blood circulation system in the human body.Both the aorta and the pulmonary artery carry blood away from the heart.Both of them originate from the ventricles of the heart.Both the arteries branch into other smaller arteries.Malfunctioning of either of these arteries causes serious diseases to humans. Aortic and pulmonary diseases are common in many individuals.