Scanning electron micrographs of human lung alveolar tissue.
a (not shown) From a non-smoker.
b From a smoker showing 'microscopic' emphysema and alveolar walls peppered by fenestrae too small to be seen by the naked eye. Such early lesions are considered to result in loss of lung elastic recoil. Scale bar = 150 micrometer
From p. 27: Jeffery, Immunopathology: Comparison of COPD and Asthma, pp.24-29