Slide A
This low-power view shows plugging of bronchioles by mucus (arrow). Some of the mucus is arranged in darkly-staining coils ("Curschmann's spirals"). There is an inflammatory infiltrate in the bronchiolar wall. The alveolar spaces appear irregular in shape, and the septa appear thickened. This actually is due to patchy atelectasis. The septa are collapsed against one another and are not really thickened.

Slide B
At high power note the mucus admixed with inflammatory cells in the lumen, the focal loss of the bronchiolar epithelium, the thickened basement membrane, the inflammatory cells in the submucosa, and the hypertrophy of the bronchiolar smooth muscle. The arrow indicates bronchiolar epithelium.