COPD features persistent airflow limitation from obstructive bronchiolitis and emphysema. Inhaled irritants activate macrophages and neutrophils releasing proteases (MMP-9, elastase) overwhelming alpha-1 antitrypsin. Mucus gland hyperplasia and goblet cell metaplasia cause chronic mucus hypersecretion. FEV1/FVC <0.7 post-bronchodilator confirms diagnosis. GOLD classification guides therapy. Connect COPD: Cellular Mechanisms to bedside cues you will reassess first: vitals trends, work of breathing, perfusion, mentation, and pain or ischemic equivalents when relevant. NCLEX items often reward recognizing when subtle instability outweighs reassurance, then selecting nursing actions that protect airway, circulation, and neurologic status before routine tasks.