Definition of free trade. : trade based on the unrestricted international exchange of goods with tariffs used only as a source of revenue.
Arteries carry oxygenated blood away from the heart to the tissues, except for pulmonary arteries, which carry blood to the lungs for oxygenation. (Usually veins carry deoxygenated blood to the heart but the pulmonary veins carry oxygenated blood.) There are two unique arteries.The pulmonary artery carries blood from the heart to the lungs, where it receives oxygen.rteries carry oxygenated blood away from the heart to the tissues, except for pulmonary arteries, which carry blood to the lungs for oxygenation. (Usually veins carry deoxygenated blood to the heart but the pulmonary veins carry oxygenated blood.) There are two unique arteries.
Key Concept The pulmonary arteries are the only arteries in the body that carry deoxygenated blood. The pulmonary veins are the only veins that carry oxygenated blood. The oxygen saturation of the hemoglobin within the arteries is normally about 95%-I00%.ey Concept The pulmonary arteries are the only arteries in the body that carry deoxygenated blood. The pulmonary veins are the only veins that carry oxygenated blood. The oxygen saturation of the hemoglobin within the arteries is normally about 95%-I00%.