Gram stain of sputum obtained before death shows Gram positive cocci in pairs. The right lung was heavy weighing 700 grams. Its lower lobe showed diffuse gray consolidation. The trachea and bronchi contained a great deal of mucus, and the mucosa was dark red.

The alveoli are distended and contain a large amount of inflammatory exudate, which consists of many polymorphonuclear leukocytes, a few RBC's, macrophages and strands of fibrin. Many RBC's have been phagocytosed by the macrophages and are undergoing disintegration. The alveolar septa are delicate and well preserved, but markedly congested.

Norm No. 24 Lung
[ImageScope] [WebScope]

The primary function of the lung is gas exchange. Therefore, alveoli have thin walls lined by thin flat pneumocytes and endothelial cells. There is no thickening or fibrosis of the interstitium. The bronchioli are lined with basally oriented ciliated columnar epithelium. The bronchi are lined by similar epithelium. There are mucous glands within the submucosa. The bronchial smooth muscle is not hypertrophied. The pulmonary vessels are patent with no evidence of intimal thickening or muscular hyperplasia.