Which term describes the surface of an epithelial cell that faces the lumen?

Which term describes the surface of an epithelial cell that faces the lumen?

• A. Basolateral surface
• B. Lateral surface
• C. Apical surface
• D. Basement membrane

Answer: (C)

Epithelial cells are organized with distinct faces: the surface that faces the lumen is the apical surface, while the opposite side sits on the basement membrane and the sides contact neighboring cells. The apical surface is specialized for interacting with the lumen contents, often bearing microvilli for absorption or cilia for moving substances along the lumen. The basement membrane lies beneath the basal surface as an extracellular support, not as a cell surface facing the lumen. Lateral surfaces are the sides between adjacent cells. So, the luminal-facing surface is the apical surface.

Epithelial cells are organized with distinct faces: the surface that faces the lumen is the apical surface, while the opposite side sits on the basement membrane and the sides contact neighboring cells. The apical surface is specialized for interacting with the lumen contents, often bearing microvilli for absorption or cilia for moving substances along the lumen. The basement membrane lies beneath the basal surface as an extracellular support, not as a cell surface facing the lumen. Lateral surfaces are the sides between adjacent cells. So, the luminal-facing surface is the apical surface.