Publisher Summary To understand the response of the respiratory system to injury, it is necessary to review the general anatomic features of the respiratory system and biology of the major cellular constituents therein. This chapter discusses these elements and focuses on the patterns of pulmonary disease, as well as mechanisms to prevent respiratory injury. The pulmonary diseases, anomalies, and disturbances are divided on the basis of pulmonary elements, such as nasal cavity, pharynx, lungs, and pleura. In the nasal cavity region, the diseases discussed are congenital anomalies, nasal amyloidosis, circulatory disturbances, rhinitis, sinusitis, and non-neoplastic proliferative disorders of the nasal. The pharynx, as the site where the respiratory and alimentary systems conjoin, is exposed to both inhaled and ingested materials, some of which may have deleterious effects on the animal. Ailments associated with pharynx described include: laryngeal paralysis, circulatory disturbances, laryngitis and tracheitis, and neoplastic diseases of larynx and trachea. After discussing lung development and its growth, the chapter emphasizes on the congenital anomalies, lung lobe torsion (atelectasis), pulmonary emphysema, circulatory disturbances of the lung (pulmonary edema, hemorrhage, vasculitis, and hypertension), pulmonary neoplasia, and anatomic patterns of lung injury (e.g., bronchial necrosis and inflammation, bronchiolar necrosis and inflammation, and bronchopneumonia). Further in the chapter, infectious diseases of the respiratory system of various veterinary animals, such as viral diseases, bacterial diseases, mycoplasmal diseases, fungal diseases, and parasitic diseases are discussed.