Ace the Histopathologic Techniques Test 2025 – Dive Into the Cellular Frontier!

In Weigert's hematoxylin, ferric chloride serves as both the mordant and the oxidizing agent. A mordant is a substance that helps fix dye to the tissue, enhancing the affinity of the dye to the cellular components, particularly nucleic acids in this instance. Ferric chloride achieves this by forming a stable complex with hematoxylin, allowing for better staining of cell nuclei.

Moreover, as an oxidizing agent, ferric chloride contributes to the conversion of hematoxylin into its active form, hematoxylic acid, which is crucial for effective staining. This dual role of ferric chloride is significant in histopathological techniques since it enhances the overall quality and clarity of nuclear staining, which is vital for accurate microscopic examination of tissue samples.

In contrast, the other options do not fulfill both functions as effectively as ferric chloride does in this specific staining protocol. Sodium iodate is primarily used for oxidation but not typically in combination with hematoxylin for mordanting; osmic acid is used predominantly for electron microscopy due to its ability to fix lipids and does not play a role in mordanting hematoxylin; while ammonium sulfate is not used in this context either.