Where are cilia or microvilli located on epithelial cells?

Where are cilia or microvilli located on epithelial cells?

• A. Apical
• B. Lateral
• C. Basal
• D. All of the above

Answer: (A)

Cilia and microvilli are found on the apical surface, the side of epithelial cells that faces the lumen or external environment. This polarity lets them do their jobs: microvilli increase surface area for absorption (as in the intestines), and cilia beat to move mucus or fluids along the surface (as in the respiratory tract). The lateral surface is where cells connect to their neighbors via junctions, and the basal surface anchors the cell to the basement membrane; these regions aren’t where cilia or microvilli are typically located. So the apical surface is the correct location for these structures.

Cilia and microvilli are found on the apical surface, the side of epithelial cells that faces the lumen or external environment. This polarity lets them do their jobs: microvilli increase surface area for absorption (as in the intestines), and cilia beat to move mucus or fluids along the surface (as in the respiratory tract). The lateral surface is where cells connect to their neighbors via junctions, and the basal surface anchors the cell to the basement membrane; these regions aren’t where cilia or microvilli are typically located. So the apical surface is the correct location for these structures.