What is the primary function of enterocytes with microvilli in the intestinal mucosa?

• A. Mechanical protection
• B. Hormone secretion
• C. Nutrient absorption and digestion
• D. Gas exchange

Answer: (C)

The main idea is that these enterocytes are built for absorbing nutrients. The microvilli form a brush border that massively increases the surface area of the intestinal lining, which is essential for efficient nutrient uptake. Enzymes anchored in the microvillar membrane (brush border enzymes) complete digestion right at the surface, and specific transporter proteins move sugars, amino acids, fatty acids, vitamins, and minerals into the cell. Once inside, nutrients cross the basolateral side to enter the bloodstream or lymphatics. This arrangement makes nutrient digestion and absorption the primary function of these cells. Mechanical protection comes from mucus and tight junctions, enteroendocrine cells handle hormone secretion, and gas exchange is not a function of the intestinal epithelium.