What epithelial type lines the majority of the conducting airways, and which cell type is most numerous within it?

What epithelial type lines the majority of the conducting airways, and which cell type is most numerous within it?

• A. Simple cuboidal epithelium; goblet cells are the most numerous.
• B. Pseudostratified ciliated columnar epithelium; goblet cells are the most numerous.
• C. Simple squamous epithelium; goblet cells are the most numerous.
• D. Stratified squamous epithelium; basal cells are the most numerous.

Answer: (B)

The conducting airways are lined by respiratory epithelium, which is pseudostratified ciliated columnar. This type looks stratified because nuclei lie at different levels, but every cell touches the basement membrane, and cilia project into the lumen to help move mucus. Among the cells in this lining, goblet cells stand out as mucus-secreting cells interspersed among the ciliated ones. The mucus they produce traps inhaled particles, and the coordinated beating of cilia carries the mucus upward to the pharynx—the mucociliary escalator. In this region, goblet cells are the most numerous among the secretory cell types, which is why they are highlighted in answers describing the epithelium of the conducting airways.

The conducting airways are lined by respiratory epithelium, which is pseudostratified ciliated columnar. This type looks stratified because nuclei lie at different levels, but every cell touches the basement membrane, and cilia project into the lumen to help move mucus. Among the cells in this lining, goblet cells stand out as mucus-secreting cells interspersed among the ciliated ones. The mucus they produce traps inhaled particles, and the coordinated beating of cilia carries the mucus upward to the pharynx—the mucociliary escalator. In this region, goblet cells are the most numerous among the secretory cell types, which is why they are highlighted in answers describing the epithelium of the conducting airways.