Which portion of the basement membrane is derived from epithelial tissue?

• A. Basal lamina
• B. Lamina reticularis
• C. Basemental crest
• D. Reticular layer

Answer: (A)

The main idea is that the basement membrane has two layers with different tissue origins. The part closest to the epithelium, the basal lamina, is produced by the epithelial cells themselves. It sits directly beneath the epithelial cells and provides attachment via proteins like laminin and collagen IV, forming a selective barrier and scaffold for the epithelium. The deeper layer, the reticular lamina, is produced by connective tissue fibroblasts and lies within the underlying stroma. So the portion derived from epithelial tissue is the basal lamina. The other options refer to components produced by connective tissue or are not standard names for basement membrane parts.