First of all, they've got FUN right there in their name. Second, Milly the milk carton had the nicest legs of any milk carton I've ever seen.
Hemoglobin is the compound in red blood cells that carries oxygen from the lungs to body cells. The oxygen combines readily with the ion in hemoglobin, and hemoglobin can carry more than twenty times its own volume in oxygen.
Therefore, most veins carry deoxygenated blood and most arteries carry oxygenated blood. However, the pulmonary veins carry oxygen rich blood to the heart, and the pulmonary arteries carry oxygen poor blood to the lungs. So, in short: no they do not carry blood all the time; the pulmonary veins carry oxygenated blood. Source(s): B.S. in Biology. MayDay Â· 6 years ago.