Air flows in and out of the lungs through tubes called airways. In COPD, the walls of the two larg...
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Air flows in and out of the lungs through tubes called airways. In COPD, the walls of the two large airways, called bronchi, are damaged and thickened. The channel air passes through is narrowed, which makes it harder to breathe. Cells in the airways that produce mucus become larger, producing more mucus, which causes a phlegmy cough. COPD also causes changes in the smaller airways, called the bronchioles. They become inflamed in response to irritating particles and gases in cigarette smoke. Excess fluid accumulates and inflammatory cells gather. They release a continuous stream of substances that produce inflammation. The substances enter the airway walls and airspaces, or alveoli, at the end of the bronchioles. The small airways are normally held open by attachments to the elastic airspace walls. When the walls are destroyed, the small airways collapse. Air is trapped in the alveoli; it is harder to fully exhale or to fill the lungs when you inhale, which leaves your body without the air it needs.
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