Which epithelium functions in absorption and secretion and includes a ciliated type to propel mucus or reproductive cells?

• A. Pseudostratified columnar epithelium
• B. Simple columnar epithelium
• C. Stratified squamous epithelium
• D. Transitional epithelium

Answer: (B)

This question tests how epithelium type supports both absorption/secretion and, in some variants, propulsion. Simple columnar epithelium is a single layer of tall, closely packed cells that lines areas where absorption and secretion are key, such as the digestive tract. Its apical surface often has microvilli to greatly increase absorptive surface and goblet cells to secrete mucus, aiding protection and lubrication. In other locations, this same cell type can be modified to be ciliated, for example in the fallopian tubes, where the coordinated beating of cilia moves the ovum toward the uterus. This combination of a single, absorptive layer with adaptations for secretion and, in some regions, ciliary propulsion fits exactly with the described function. Other epithelia are mainly protective (stratified squamous), distensible but not absorption-focused (transitional), or primarily involved in mucus propulsion without the same absorptive role (pseudostratified in some contexts).