wavelength waveÂ·length (wÄv'lÄngkth', -lÄngth') n. Symbol Î» The distance between one peak or crest of a wave of light, heat, or other energy and the next corresponding peak or crest.
Causes: Emphysema: The number one cause of emphysema is smoking. Other contributing factors in its development or exacerbation (increase in severity) include long-term exposure to other lung irritants, such as air pollution, chemical fumes, or dust.
Emphysema caused by smoking most often occurs in the upper lobes of the lungs. In chronic bronchitis, smoking triggers inflammation that causes damage in the airways. The processes involved include: 1  Damage to the cilia, the hair-like waving projections that move mucus, bacteria, and foreign particles out of the lungs. 2  Enlargement of the mucus glands in the large airways of the lungs. 3  Overgrowth of smooth muscle cells in the airway.