Blood vessel prevent backflow as a result of a decrease in blood pressure as the blood passes through the circulatory system. There are various kinds of blood vessels: They are roughly grouped as "arterial" and "venous", determined by whether the blood in it is flowing "away from" (arterial) or "toward" (venous) the heart. The term "arterial blood" is nevertheless used to indicate blood high in oxygen, although the pulmonary artery carries "venous blood" and blood flowing in the pulmonary vein is rich in oxygen. This is because they are carrying the blood to and from the lungs, respectively, to be oxygenated. Blood
Blood red Blood red The color blood red is a dark shade of the color red meant to resemble the color of human blood (which is composed of oxygenated red erythrocytes, white leukocytes, and yellow blood plasma). It is the iron in hemoglobin specifically that gives blood its red color. The actual color ranges from crimson to a dark brown-blood depending on how oxygenated the blood is, and may have a slightly orange hue. Deoxygenated blood, which circulates closer to the body's surface and which is therefore generally more likely to be seen than oxygenated blood, issues from bodily veins in a