The circulatory system is often seen to comprise both the cardiovascular system, which distributes blood, and the lymphatic system, which circulates lymph. These are two separate systems.The passage of lymph for example takes a lot longer than that of blood.Blood is a fluid consisting of plasma, red blood cells, white blood cells, and platelets that is circulated by the heart through the vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues.he circulatory system is often seen to comprise both the cardiovascular system, which distributes blood, and the lymphatic system, which circulates lymph. These are two separate systems.