ABSTRACT
This chapter argues that information in order to provide an overview of the current concepts relating to possible causes and pathogenesis of this disease. Normal structure and function of the lung will first be described, followed by the manner in which the alteration in structure affects pulmonary function in emphsyema. The normal lung is a complex organ originating as an outpouching of the foregut and composed of endodermal epithelium and splanchnic mesenchyme. The normal lung is composed mainly of connective tissue macromolecules, lipids, over 40 cell types, and a high percentage of air. Larger airways are lined with ciliated columnar epithelium and mucus-secreting cells. Pulmonary veins are located in the connective tissue septae between individual lobules. Alveoli comprise the gas-exchanging region of the lung. The alveolar wall alternates between thick regions, composed of connective tissue and cells, and thin regions, containing an attenuated alveolar capillary, composed only of an endothelial cell and the contents of the capillary.
