What is the epithelial lining of the trachea?

• A. Pseudostratified ciliated columnar epithelium with goblet cells
• B. Simple squamous epithelium
• C. Simple cuboidal epithelium
• D. Stratified squamous epithelium

Answer: (A)

The trachea is lined by respiratory epithelium, specifically pseudostratified ciliated columnar epithelium with goblet cells. The term pseudostratified means all cells touch the basement membrane, but nuclei lie at different heights, giving a layered appearance. This epithelium has tall ciliated cells that beat toward the pharynx and goblet cells that secrete mucus, which traps inhaled debris and microbes. The coordinated ciliary movement (the mucociliary escalator) then clears mucus out of the airway, protecting the lungs. Other options describe tissues better suited for diffusion or abrasion resistance and lack the cilia-goblet apparatus needed for mucus-based cleaning, so they wouldn’t function effectively as the tracheal lining.