This report provides a comprehensive overview of Chronic Obstructive Pulmonary Disease (COPD). It begins by defining COPD and outlining its symptoms, including wheezing, breathing difficulties, and cough. The report highlights that COPD is often caused by long-term exposure to irritants such as cigarette smoke, chemical fumes, and dusts. The report also provides interesting facts about the disease, such as the global prevalence and the financial burden it places on healthcare systems. It then explains the normal anatomy and physiology of the respiratory system, including the roles of lung compliance, airway resistance, and ventilation. Furthermore, the report details how COPD impacts normal anatomy and physiology, leading to changes like loss of elasticity in the bronchioles, airway damage, and obstruction. The report also defines key terms like inflammation, wheezing, airway resistance, airway obstruction, and emphysema to enhance understanding. The report's overall objective is to provide a clear understanding of COPD, its causes, its effects on the body, and the mechanisms involved.