The circulatory system consists of the heart and blood vessels, responsible for pumping blood and substances throughout the body. It features a double circulatory system with the right side handling deoxygenated blood and the left side dealing with oxygenated blood, utilizing arteries, veins, and capillaries for blood transport. Blood contains red blood cells, white blood cells, platelets, and plasma, each with specific roles including oxygen transport, disease protection, and clotting.