Phosphotungstic acid hematoxylin demonstrates which tissue components?

• A. Myelin and glial fibers
• B. Myelin only
• C. Glial fibers only
• D. Nerve fibers

Answer: (A)

Phosphotungstic acid hematoxylin is used to highlight neural tissue elements by producing a strong blue-black coloration in components rich in certain proteins and filaments. It binds to the myelin sheath surrounding axons and to the glial filament networks within neuroglial processes, making both structures stand out clearly. This dual staining is what lets you visualize both myelin and glial fibers with this stain.

That’s why the best answer is the option describing both myelin and glial fibers. If a description only mentioned myelin or only glial fibers, it wouldn’t capture the full staining behavior of PTAH. Likewise, labeling something as just nerve fibers is too vague because PTAH emphasizes the specific neural components—myelin and glial filaments—rather than indiscriminately staining all nerve fibers.