ABSTRACT
This chapter discusses the broad range of phenotypes, surface marker expression, and mediators secreted by the epithelium of the lung. A continuous layer of epithelial cells lines the entire respiratory tract. Ciliated cells are a major part of the body’s defense against inhaled pathogens and noxious particles. Serous cells are another class of secretory cells that contribute to the fluid bathing the surface of the epithelium. Neuroendocrine cells also reside in the basal region of the epithelium and typically have thin cytoplasmic extensions to the luminal surface. Epithelial cell–cell adhesion is essential for the airway epithelium to function as a physical barrier to potentially harmful inhaled agents. A variety of proteins and glycoproteins make up the different portions of the desmosome. A broad range of adhesion molecules is expressed on the surface of epithelial cells. The principal adhesion molecules involved in the binding of epithelial cells to basement membrane are the integrins.
