1.The movement of the columnar cell cilia removes this mucus from the airways in the opposite direction to the inhaled air, to the oral cavity.As the airways branch and the bronchial diameter decreases, the height of the epithelial cells decreases, the number of goblet cells decreases, and then the number of cilia also decreases.Among them, two types of cells are distinguished: some are immature cells, which can give rise to ciliated or goblet cells; the others have nerve endings on their basal surface and are able to perform a receptor function.Small granule cells, resembling basal cells, but contain numerous cytoplasmic granules.Respiratory mucosa is composed of respiratory epithelium and lamina propria. 2)- pseudostratified columnar ciliated epithelium with goblet cells.Ciliated columnar cells predominate in the respiratory epithelium.