The respiratory system helps you breathe. The main parts of the respiratory system are the lungs, the airways, and the muscles that enable breathing. The circulatory system, which is made up of the heart, veins, arteries, and capillaries, brings blood to and from the lungs and delivers nutrients and oxygen to tissues of the body while removing carbon dioxide and waste products. Other body systems that work with the respiratory system include the nervous system, lymph system, and immune system.