Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, and the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, acute asthma, lung cancer, and severe acute respiratory syndromes.
