Sections for demonstration of basement membranes should be cut at which thickness?

• A. 1 nm
• B. 2 nm
• C. 5 nm
• D. 10 nm

Answer: (B)

Visualizing a basement membrane requires electron microscopy, because these structures are ultrastructural and too thin for light microscopy. To clearly see the distinct layers of the basement membrane, the section must be extremely thin so electrons can pass through with minimal scattering and the ultrastructure remains intact. Among the given options, 2 nanometers best meets this ultrathin requirement, providing the greatest electron transmission and contrast for resolving the delicate lamina rara, lamina densa, and their interface. Thicker sections (such as 5 or 10 nanometers) would scatter more electrons and blur the layers, while 1 nanometer, though thinner, is often not reliably obtainable or mechanically stable.