The document provides information on the circulatory system, including its key features and functions. There are two main types of circulatory systems - open and closed. In an open system, fluid circulates through an open body chamber while in a closed system, blood vessels circulate blood. Closed systems allow for larger body sizes as they are more efficient at oxygen transport. The circulatory system also includes blood, which contains plasma, red blood cells, white blood cells and platelets. It transports through a network of arteries, veins and capillaries. The heart pumps blood through the system in vertebrates.