(a) Schematic overview of the lung within the body. (b) Left lung lobe marking the distal part of the lung. (c) Magnification of the distal lung, represented as a cross-section through the distal airways and the alveolar region. The surface of the lung is formed by a continuous epithelial layer consisting of different cell types. In the airways the bulk of epithelial cells are cuboidal cells with cilia. In the alveolar region, the epithelium is formed by alveolar type I and alveolar type II cells.
