Heart is part of circulatory system. and in circulatoryof a human there are 2 types of circulations. in pulmonary circulation the lungs is involve. because during this process the deoxygenated blood or the blood without oxygen will enter in right atrium then will be pumped in right ventricle then it will reach the lungs wherein airsacs are located. in airsacs , the oxygen are stored. so the blood will undergo diffusion. the oxygen will transfer to the blood then tha carbon dioxide from the blood will transfer to the lungs. and from the lungs, the carbondioxide will exit from the body through breathing. and the blood with oxygen will now enter systemic circulation.