Tidal Volume vs. Vital Capacity: Understanding Lung Capacity

• Tidal Volume (TV): Air moved in quiet breathing (500–800 mL).
• Inspiratory Reserve Volume (IRV): Extra air inhaled beyond TV (3,000–3,500 mL).
• Expiratory Reserve Volume (ERV): Extra air exhaled beyond TV (1,000–1,200 mL).
• Residual Volume (RV): Air remaining after maximal exhalation (1,000–1,200 mL); prevents collapse.
• Vital Capacity (VC): Maximal forced exhalation after maximal inhalation = TV + IRV + ERV (3,500–5,000 mL).
• Total Lung Capacity (TLC): VC + RV = total lung volume (5,000–6,000 mL).