What does basal mean?

• A. Faces the basal lamina or basement membrane.
• B. Faces the free surface.
• C. Is opposite to apical.
• D. Is involved in nerve conduction.

Answer: (A)

Basal refers to the surface of epithelial cells that faces the basement membrane, also called the basal lamina. This boundary sits between the epithelium and the underlying connective tissue and is where the basal surface anchors the cells (often via hemidesmosomes). Because of this attachment, the basal side is defined by its contact with the basement membrane, which is why the statement that it faces the basal lamina or basement membrane is the correct way to describe basal. In contrast, the apical surface faces the free or lumen-facing side, and nerve conduction is a property more relevant to neurons than to epithelial tissues.