Chronic obstructive pulmonary disease COPD and its treatments. Top left lungs with the bronchial tree in transparency, from which a sub-segmental bronchus in zoom. A left sectioned bronchiole is normal. The right sectioned bronchiol exhibits bronchoconstriction with hypersecretion of mucus, inflammatory cells producing cytokines in the mucosa. At the bottom the pulmonary lobules. On the left the alveolar sacs are normal, on the right, an emphysema seen in section shows the distended cells.