Without oxygen, no part of the body–not the brain, the heart, the legs, the arms, or anything else–would work. The lungs are the most important component of the respiratory system, the process by which oxygen is supplied to all living cells. Readers will discover how we breathe, how oxygen affects metabolism, and the relationship between the heart and lungs. Full-color images and clearly labeled diagrams illuminate every detail of the lungs’ structure and functions.