Blood vessels that carry blood away from the heart. The arteries in the Pulmonary circulation, the transfer of blood cells between the heart and the lungs, carry oxygen-poor blood while the arteries in the systemic circulation, the circulation of blood cells between the heart and the rest of the body, carry oxygen-rich blood. Arteires have strong walls to withstand the continuous pressure exerted by the ventricles. Arteries have an outer wall made up of Connective tissue, an intermediate wall made up of Smooth muscle, and an inner wall made up of Endothelium. [1]