Which features support absorption and secretion with microvilli and goblet cells?

• A. Simple or columnar epithelium (e.g., intestinal) with microvilli for absorption and goblet cells for mucus secretion.
• B. Simple squamous epithelium with microvilli for diffusion
• C. Stratified squamous epithelium with goblet cells
• D. Pseudostratified columnar epithelium without goblet cells

Answer: (A)

Absorption and secretion are best supported by an epithelium that provides a highly folded, expansive surface for nutrient uptake and additional cells that produce mucus to protect and lubricate the lining. In the intestinal lining, the simple columnar epithelium has microvilli on the apical surface, forming a brush border that greatly increases surface area for efficient absorption and hosts brush-border enzymes to aid digestion. Interspersed goblet cells secrete mucus, which lubricates the lumen, traps particles, and protects the epithelium during passage of contents. This combination—an absorptive, tall columnar layer with microvilli plus mucus-secreting goblet cells—directly supports both absorption and secretion.

Other options miss this pairing: simple squamous epithelium is thin and optimized for diffusion rather than active absorption and mucus production; stratified squamous is protective against abrasion and not specialized for mucus secretion; pseudostratified columnar can line mucosal surfaces but without goblet cells the mucus-secreting support is lacking and absorption is not the primary function.