Which type of cell junction would be most critical in maintaining the integrity of the blood-brain barrier, and why?

• A. Tight junctions, because they prevent the passage of substances between cells.
• B. Gap junctions, because they allow communication between neurons.
• C. Desmosomes, because they provide mechanical strength.
• D. Adherens junctions, because they anchor cells to the extracellular matrix.

Answer: (A)