Eric, good morning. With regard to your question, consider the following. As you have noticed your blood is red because red blood cells have an iron-containing substance called hemoglobin, which reacts with oxygen to make blood red. The blood in your arteries is moving away from your heart and lungs. So it’s a bit more oxygenated than blood in your veins which is blood that’s given up some of its oxygen to the body and is now on its way back to the lungs. While blood from a vein may look purplish when drawn into a sealed tube, however you never see blue blood because no blood in your body is truly blue. An optical effect involving the way pale skin, and the tissue beneath, absorb and reflect light result in this purplish color of veins.
