Is deoxygenated blood blue?

     A common misconception, the concept of blue blood has been around ever since keen observers began exploring the wonders of the cardiovascual system. The reasoning behind this misleading theory seems to stem from the fact that our veins - which carry deoxygenated blood - appear to be blue to us, and thus, their contents musat reflect this stark color. The reality however is far less conclusive. This theory goes under several assumptions, namely assuming that veins are transparent enough to emit the color of the blood they carry, and relies heavily on the concept that it is only oxygen that gives blood its crimson hue.

    Prior to defeating this misleading theory which seems to have alluded many a biology teachers and some students, time should be allotted to discuss the science behind oxygenated red blood. Blood contains millions of hemoglobins which attach to oxygen molecules, releasing them to every individual cell in the body. The oxygen-enriched blood cells are bright red in color due to the oxidation of the iron present in each hemoglobin protein. When the oxygen vacated the hemoglobin, the cell defaults to its original state - dark red. This is why blood drawn into a vacuum (e.g. a syringe)  remains a solid red color, and blood released in oil will remain red despite any contact with oxygen.

     So then why are veins blue? It should be noted that colour is not necessarily a property, but just wavelengths of light being reflected towards the observer. Human fat allows only blue light to penetrate deep into the veins, and the deoxygenated blood only further absorbs the darker wavelengths. The end result appears to be a dark and blue vein that appears to carry bluish blood. Any meat aficionado will be able to tell you that veins are not distinguished from other blood vessels, and instead appear brownish-red in color.