Hematoxylin and Eosin Staining Flashcards
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Read the first 6 Hematoxylin and Eosin Staining flashcards as text
What cellular component is primarily stained by hematoxylin in an H&E stain?
Answer: Nuclei (DNA/RNA)
Hematoxylin is a basic dye that binds to negatively charged nucleic acids in the nucleus, staining it blue-purple.
What color does eosin stain the cytoplasm and collagen in a routine H&E preparation?
Answer: Pink/red
Eosin is an acidic dye that stains positively charged proteins in the cytoplasm and extracellular matrix pink to red.
What is the purpose of the mordant in the hematoxylin staining process?
Answer: To link the hematoxylin dye to tissue components
A mordant (typically alum) acts as a bridge between the dye and tissue, forming a stable dye-mordant-tissue complex.
What is the 'bluing' step in H&E staining intended to accomplish?
Answer: Convert soluble hematoxylin to an insoluble blue-black complex by raising pH
Exposure to a slightly alkaline solution (Scott's water or ammonia water) shifts the hematoxylin complex from red-brown to a permanent blue-black.
What is the purpose of the differentiation step using acid-alcohol in H&E staining?
Answer: To selectively remove excess hematoxylin from non-nuclear elements
Acid-alcohol removes excess hematoxylin from cytoplasm and connective tissue, leaving stain only in the nuclei.
Before H&E staining, paraffin sections must be deparaffinized using which reagent?
Answer: Xylene
Xylene dissolves paraffin wax before the section is rehydrated through graded alcohols for aqueous staining.