Tobacco Smoke and Alveolar Cell Populations

Abstract

The selective study of alveolar cell populations is justified by the physical characteristics of tobacco smoke and by the nature of the disorders observed in the clinic. Before developing this point several preliminary remarks concerning the deep lungs have to be made: What is the exact definition of the deep lung? If one gives an animal, for instance a rat, an aerosol with a radio-active labelled element and records the decrease of radio-activity, one obtains in semi-logarithmic co-ordinates a curve with 3 compartments: a rapid compartment which corresponds to the tracheo-bronchial clearance, an intermediate semi-slow one and a slow compartment (Fig.l). This curve is reduced to two compartments in man (Fig.1). The deep lung corresponds to this slow clearance compartment which involves a retention of particles for a long time. This is, in fact a physiological notion expressing clearance. This notion includes not only the structures for gas-exchange but also the terminal conductive air-ways. In other words there is a bronchio-alveolar unit whose cells cannot be functionally separated in terms of clearance.