Scorpions have an open circulatory system, which means that they do not have blood vessels so the blood fills the body cavity and the cells are surrounded by blood. A scorpions blood does not contain hemoglobin to carry the oxygen to the cells, so scorpions use the proteins hemolymph, which contain fats, sugars, hormones and water. The dorsal vessel acts like a heart because it keeps the hemolymph moving around the body. The hemolymph contains nutrients that the body needs. No arteries, veins, or capillaries used in the circulatory system.