What is a primary function of simple columnar epithelium?

• A. Absorption and secretion
• B. Protection and support
• C. Rapid nerve conduction
• D. Contraction of underlying muscles

Answer: (A)

Absorption and secretion are the primary functions of simple columnar epithelium. This tissue forms a single layer of tall, column-like cells that line much of the digestive tract and certain ducts. The apical surface often has microvilli, which greatly increase surface area for nutrient absorption, while goblet cells secrete mucus to protect and lubricate the lining. Some cells also secrete enzymes or participate in selective transport, supporting these absorptive and secretory roles. In contrast, protection and support are characteristic of other epithelia, rapid nerve conduction is a feature of nervous tissue, and contraction of underlying muscles comes from muscle tissue, not the epithelium.