Histotechnology - Fixatives, Stains questions well answered graded A+ 2023/2024

Histotechnology - Fixatives, StainsAdditive fixatives - correct answers Chemically link, add themselves on to tissue and change it - Mercuric chloride - Chromium tetroxide - Zinc sulfate Nonadoptive fixatives - correct answers Organic compounds that act on tissue without chemically combining with it - Acetone - Alcohols Dissociate bound water molecules from tissue protein groups - Shrinkage, hardening with overexposure Coagulant fixatives - correct answers Establishes a network in tissue that allows solutions to readily penetrate or gain entry into the interior of the tissue - Zinc salts - Mercuric chloride - Cupric sulfate - Ethyl/methyl alcohol - Acetone - Picric acid Noncoagulant fixatives - correct answers Create a gel that makes penetration by solutions difficult - Formaldehyde - Glutaraldehyde - Glyoxal - Osmium tetroxide - Potassium dichromate Ideal temperature for fixation for EM - correct answers 0-4C Temperature in tissue processors - correct answers Up to 45C Volume ratio - correct answers 15-20:1 Time in formalin - correct answers 6-48 hours Masson trichrome - correct answers Formalin fixation Mordant with Bouin's Orth solution - correct answers Chromaffin granules for pheochromocytomas Absolute alcohol - correct answers Urate crystals pH of 10% NBF - correct answers 6.8 Hypotonic Exposure limit to formaldehyde - correct answers Long term - 0.75 ppm over 8 hour period Short term - 2 ppm over 15 minute period Action level limit of formaldehyde - correct answers 0.5 ppm over 8 hour period Glutaraldehyde (2-4%) - correct answers Cannot be used with PAS - False positives Used for electron microscopy - 2 hours fixation 0.05 ppm threshold limit Osmium tetroxide - correct answers Preserves fats Potassium dichromate - correct answers Preserves mitochondria by rendering lipid component insoluble Zinc salts - correct answers Substitute for mercury in B5 solution Higher DNA yield B5 - correct answers Hematopoietic and lymphoreticular tissue Demonstrate nuclear detail Bouin's - correct answers Lyses RBCs Trichrome stain Brilliant nuclear and cytoplasmic staining with H&E - Good for GI tract biopsies