Epithelial Lining of the Pharynx.
The surface of the nasopharynx is covered by the same pseudostratified columnar epithelium that is found in the nasal cavity. Goblet cells in the epithelium secrete mucus, which further cleans, warms, and moistens incoming air before it moves deeper into the respiratory tract.
Along the oropharynx and laryngopharyx the epithelium changes to nonkeritonizing stratified squamous epithelium. This portion of the respiratory passageway is shared with the digestive tract, and the multiple cell layers in the epithelium helps protect the underlying tissues from damage caused when food is swallowed.
