A detailed look at the respiratory system and how it works.
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Chronic bronchitis is long-term inflammation of the breathing tubes (bronchi). Learn more about this condition, including causes, symptoms, diagnosis, and treatment.
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Emphysema is a chronic lung condition in which the air sacs (alveoli) may be destroyed, narrowed, collapsed, stretched, or overinflated. Pulmonary emphysema is part of a group of lung diseases called COPD. Here's what you need to know.
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