Anterior view of the lungs and alveoli showing the comparison of a healthy respiratory system and a respiratory system affected by chronic obstructive pulmonary disease (COPD). The bronchi and alveoli of the healthy lungs are elastic and open, allowing oxygen to easily pass into the blood vessels. The bronchi and alveoli of the lungs affected by COPD are stretched out and many alveoli walls are destroyed. There is also inflammation and mucus restricting the airways, making it more difficult to breathe.
