The Circulatory System in all organisms is responsible for the flow of blood and other nutrients throughout the body. These nutrients help form cells throughout the body of all orgnisms. There are different types of circulatory systems for different animals. The circulatory system gets more complex as the phylums get more complex. Some organisms do not have a circulatory system at all, but other systems, such as the digestive system, help with the diffusion of nutrients. Other natural conditions that the organisms are in can help diffuse these nutrients and expell waste aswell.