How is pseudostratified epithelium described?

• A. It is a single layer with all cells touching the basement membrane; example: trachea.
• B. It consists of multiple layers with some cells not reaching the basement membrane; example: skin.
• C. It appears layered but all cells touch the basement membrane; example: trachea.
• D. It stretches and is found in the bladder.

Answer: (C)

Pseudostratified epithelium looks layered because the nuclei lie at different heights, but every cell actually rests on the basement membrane, so it is a single layer. This arrangement is common in the trachea, where the cells are often ciliated and include goblet cells to help move mucus out of the airways. The key descriptor that fits this tissue is that it appears multi-layered yet all cells touch the basement membrane, with the trachea as a classic example. The other descriptions describe true simple epithelium (one layer with all cells touching the basement membrane), stratified epithelium like skin, or transitional epithelium of the bladder, none of which capture the distinctive look-and-touch pattern of pseudostratified epithelium.