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26 Cards in this Set
- Front
- Back
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autolysis |
destruction or digestion of tissues and cell by the enzymes normally present in the cells.
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fixation
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the stabilization of protein
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artifact
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a structure or substance not normally present but produced by some external force or action. Examples are mercury pigment, tissue floaters, knife lines and air bubbles.
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pigment
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a heterogeneous group of substances that contain enough natural color to be visible without any further staining. Ex melanin, hematin
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coagulating fixative
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establishes a network in the tissues that allows solutions to readily penetrate into the interior of the tissue. alcohol, zinc salts, mercuric chloride, chromium trioxide, picric acid.
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additive fixative
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chemically link to the tissue and change it with this action. Ex mercuric chloride, chromium trioxide, picric acid, formaldehyde, glutaraldehyde, osmium tetroxide, zinc sulfate
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acetic acid
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not a fix for carbs and lipids. noncoagulant. Added to other fixs to counteract shrinking. Causes tissue to swell.
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acetone
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non additive. used with enzymes. Can cause extreme shrinkage, distortion, and overhardening.
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alcohols
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Preserves water soluble tissue components. Ex. glycogen and urate. Nonadditive. Breaks down hydrogen and ionic bonds. Frees groups to interact with reagents, mordants, and stains. Dissolves fat, overhardens and shrinks tissue.
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B-5 fixative
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Mercuric chloride, sodium acetate, formaldehyde. Fixative of hematopoietic and lymphoreticular tissues. Demo nuclear detail. Remove mercury pigment with iodine and sodium thiosulfate. Tissue can't be stored.
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Bouin solution
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picric acid, formaldehyde, acetic acid. Trichrome stains. preserve delicate features. Swelling of acetic acid balanced by shrinking of picric acid. Post fix wash with EtOH. No storage. GI tract, endocrine system.
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Carnoy and methacarn solutions
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EtOH, chloroform, acetic acid. rapid acting, preserves glycogen. good nuclear preservation. Excessive shrinkage and hardening. No storage.
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formalin
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37-40% formaldehyde solution. noncoagulant and additive. lipid groups preserved. acts on amino side chain group. Penetrates and adds quickly. Less shrinkage than any other fix. Hardens more except for acetone and ethanol. Hypertonic, but not osmotic.
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gendre solution
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alcohol saturated with picric acid, formaldehyde, acetic acid. preserves some carbs. Remove excess picric acid with EtOH.
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glutaraldehyde
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dialdehyde. acts like formaldehyde. extra group interacts with Schiff reagent. Can't use with PAS stain. Penetrates slowly and poorly. Use for EM. No storage.
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Helly solution
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mercuric chloride, potassium dichromate, sodium sulfate, formaldehyde. Formaldehyde is reducing agent=unstable solution. Treat for mercury pigment postfix. No storage. Decrease nuclear basophilia and increase cytoplasmic acidophilia.
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Hollande solution
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Copper acetate, picric acid, formaldehyde, acetic acid. Modification of Bouin. Stable will decalcify small bone. GI tract, stablizes RBC, eosinophils and endocrine cells. Must wash or form phosphate precipitate.
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mercuric solution
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very corrosive. powerful protein coagulant. enhances staining. Inhibits freezing. Shrinkage. Will harden excessively. Additive. Must remove pigment. Treat with iodine then sodium thiosulfate.
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Orth solution
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Potassium dichromate, sodium sulfate, formaldehyde.
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osmium tetroxide
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post fix for EM. Fixes lipids. Hazardous and expensive. Additive. LIttle affinity for anionic (acid) dyes. Binds cationic (basic) dyes.
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paraformaldehyde
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polymerized form of formaldehyde
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potassium dichromate
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Noncoagulant. Rarely used alone. Act like chromic acid when used with acids=coagulant. Preserves some lipids. Dissolves DNA. Shrinks. Increases basic groups and increased affinity for eosin. Treat with acid and EtOH to remove pigments.
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Zamboni solution
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paraformaldehyde, picric acid. Very stable. Good general purpose fixative.
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Zenker solution
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Mercuric chloride, potassium dichromate, sodium sulfate, acetic acid. Very similar to Helly.
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zinc formalin
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zinc chloride, formaldehyde. Can result with formalin pigment. No storage.
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Fixatives for nucleic acids
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acetic alcohol and carnoy solution
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