Did You Know!
While blood appears red when oxygenated and travels through arteries, it can appear bluish-purple when it lacks oxygen and is traveling back to the heart through veins. The iron-containing molecule hemoglobin is what gives blood its red color when oxygenated. However, when blood is deoxygenated, such as in veins returning to the heart, it appears darker due to the lack of oxygen bound to hemoglobin.
