The human lungs are located in the thoracic cavity and are the main organs in the chest cavity, divided into the left and right lungs, each of which is divided into several lobes, the left lung being two lobes and the right lung being three lobes. The lungs are the respiratory organs of the human body, the place of gas exchange, connected to the larynx and nose through the trachea and bronchi, etc. Through respiration, they realize the gas exchange between the organism and the external environment, constantly inhaling oxygen and expelling carbon dioxide to maintain the normal activities of life. The role of the lungs is to maintain the normal metabolism of the body through the exchange of gases between the body and the outside world. Second, the lung is the main propagator and purifier, expelling all kinds of foreign substances in the lung, so that the airway is open and the breathing is smooth.