The document summarizes key aspects of the circulatory system including: - The major parts of the circulatory system including the heart, veins, and arteries. - The heart pumps oxygenated blood through the arteries and deoxygenated blood returns through the veins. - The circulatory system interacts with other body systems to transport materials throughout the body and helps maintain homeostasis, for example by regulating body temperature. - Some common diseases that can affect the circulatory system are discussed like heart attacks, aneurysms, and leukemia. Blood clotting and common questions are also addressed.