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Flashcards

Histotechnology

Victoria Station Histotechnology English 55 cards

Cards in this deck (55)

  1. 1What fixative is used for routine tissue fixation? What is the minimum time required?formalin
    2 hours minimum
  2. 2How much fixative is required for a specimen?15-20x more than the specimen
  3. 3What occurs to tissues over time if they are not fixed?details lost
    stainability lost
    cells come away from basement membrane
    cytoplasm swells, becomes granular
    gas bubbles in tissue (putrefaction)
    karyolytic nucleus
  4. 4how is "fresh" tissue treated?no fixative
    maximum 30-45 min
    saline soaked gauze
    4oC
  5. 5How are tiny tissues / biopsies handled?using lens paper and smaller cassettes
  6. 6How long are the short and long processing times?short 6 hours
    long 13 hours
  7. 7What sort of things occur during grossing?marking tissues (margins, up/down)
    measuring size
    color
    shape
    weight
    abnormalities
  8. 8What are the features of a cassette? (size, colour, shape etc)0.3 cm deep
    max size is 2 x 3 x 0.3
    colours indicate the type of specimen
    holes in the cassette for fluid flow
  9. 9What is the purpose of fixation?chemically inactivates enzymes and stabilizes proteins to prevent degradation
  10. 10What are other methods of fixation?heat
    desiccation
    (chemical)
  11. 11How are CJD specimens handled?extended, special fixation: 1 week in phenolized formalin
  12. 12What are 8 factors affecting fixation- time
    - size of tissue
    - volume of fixative
    - temperature
    - type of fixative
    -density of tissue
    - non/additive
    - non/coagulant
  13. 13What are the COAGULANT fixatives and what is their mode of action?Zinc, Alcohol, Picric Acid, Acetone, Mercury
    produces a network in tissue to allow solutions to penetrate
  14. 14Why are coagulant fixatives mostly found in compounds? ex B5they are heavy and cause a lot of precipitation
  15. 15What are the NONCOAGULANT fixatives and what is their mode of action?formalin, gluteraldehyde, osmium tetroxide, acetic acid
    create a gel that makes penetration difficult (cytoplasm becomes a gel)
  16. 16What are the ADDITIVE fixatives and what is their mode of action?Formalin, Mercuric Chloride, Chromium Tetroxide, Picric Acid, Gluteraldehyde, Osmium Tetroxide, Zinc Sulfate
    chemically combines with protein to become insoluble
  17. 17What are the NONADDITIVE fixatives and what is their mode of action?Alcohol, Acetone, Acetic Acid
    protein unable to maintain relationship with water
  18. 18What generally happens to different cell constituents during fixation? nucleic acid, proteins, lipids, carbsnucleic acids do not react
    proteins altered
    lipids mostly lost
    carbs some lost
  19. 19What is a microanatomical fixative? What are 4 examples?Microanatomical fixative allows the cells to retain their former relationship with each other
    - Formalin
    - Bouin's
    - Gluteraldehyde
    - Zenker / Helly
  20. 20What are cytological fixatives? What are 2 examples?Fixatives that preserve the intracellular structures of tissue
    - 95% alcohol
    - acetic acid
  21. 21What are histochemical fixatives? What are 5 examples?Fixatives that preserve enzymes or other elements like glycogen, lipids, etc
    - mercuric chloride
    - picric acid
    - ethanol
    - acetone
    - zinc
  22. 22Best general fixative?10% Neutral Buffered Formalin
  23. 23Best fixative for nucleic acids?Acetic Acid
  24. 24Best fixative for cytoplasm?Bouin's
    or
    B5
  25. 25Best fixative for lipids?osmium tetroxide
    formalin
    or
    potassium dichromate
  26. 26Best fixative for enzymes?acetone
  27. 27Best fixative for glycogen?alcohol
  28. 28Best fixative for cytology?95% alcohol
  29. 29Best fixative for blood smears?methyl alcohol
  30. 30What type of fixative is Formalin? What is its composition? What does it do to tissue?non-coagulant, additive
    37-40% formaldehyde gas in water
    creates methylene bridges
    increases basophilia
  31. 31How does Acid Formaldehyde Hematin occur? How is this removed?Occurs when blood is present in tissue and the pH of the fixative is less than 6.0
    Remove with alcoholic picric acid
  32. 32How to dispose of formalin1:5 with Formalex
  33. 33How are frozen sections possible if a tissue is fixed with formalin?Methylene bridges reversible by rinsing with water
  34. 34What type of fixative is Acetic Acid? What does it do to tissue?non-coagulant, non-additive
    swells tissue, lyses RBCs, fixes nuclei
  35. 35What type of fixative is Picric Acid ? What does it do to tissue?coagulant, additive
    destroys DNA/RNA, decalcify, increase acidophilia, dissolves iron, stains tissue yellow
  36. 36What type of fixative is Potassium Dichromate? What does it do to tissue?coagulant, additive
    preserves mitochondria
  37. 37How do you remove pigment after fixing with Potassium Dichromate?washing with water
  38. 38What type of fixative is Gluteraldehyde? What does it do to tissue?noncoagulant, additive
    crosslinking of proteins but no methylene bridges
    fixes slowly and poorly
  39. 39Why does gluteraldehyde cause a false positive in PAS stain?adds an extra aldehyde group to tissue
  40. 40What type of fixative is Mercuric Chloride? What does it do to tissue?coagulant, additive
    increases acidophilia and basophilia
  41. 41What type of fixative is B5? What is its composition? What does it do to tissue?coagulant, additive
    mercuric chloride, sodium acetate, water
    layered fixation, enhances staining, good antigen preservation
  42. 42Why has mercuric chloride been replaced by zinc formalin?Safer - mercury is a heavy metal
    mercury is radio-opaque
    mercuric pigment
    inhibits freezing
  43. 43How can you remove mercuric pigment from tissue?Dezenkerization
    alcoholic iodine and sodium thiosulfate
  44. 44Tissue was fixed with Mercuric Chloride and produced mercuric pigment. What stain would not require prior dezenkerization?Verhoeff's van Giesen (because it contains alcoholic iodine and sodium thiosulfate)
  45. 45What type of fixative is Osmium Tetroxide? What does it do to tissue?non-coagulant, additive
    fixes lipids by chemically combining with them and making them insoluable
    decrease affinity for acidic dyes
  46. 46Bouin's: What is its composition? What does it do to tissue?picric acid + formaldehyde + glacial acetic acid
    preserves nucleic and chromosomes
    enhances Trichrome
    lyses RBCs
  47. 47How is the yellow colouration from picric acid removed?70-80% alcohol
  48. 48What is PAF/Zamboni: What is its composition?parafromaledhyde + picric acid
    stable and good general all purpose fixative
  49. 49What type of fixative is Zinc Formalin? What is it good for?coagulant, additive
    replaces mercury in B5
    good for lymph nodes in IHC
  50. 50What type of fixative is Acetone? What does it do to tissue? What is it good for?coagulant, non-additive
    shrinks and hardens, fixes and dehydrates
    good to demonstrate enzymes (IHC)
  51. 51What type of fixative is Ethanol/Alcohol? What is its composition? What does it do to tissue? What is it good for?coagulant, non-additive
    95% concentration
    inhibits freezing, over-hardens and shrinks
    good for cytology, cell preservation, and preservation of glycogen
  52. 52Carnoy: What is its composition? What does it do to tissue? What is it good for?alcohol + chloroform + glacial acetic acid
    lyses RBCs and preserves glycogen
    good for cytology and nuclear fixation
  53. 53What are 3 transport solutions?Michael Transport Solution
    RPMI for flow cytometry
    saline
  54. 54What is layer fixation?Fixation slows as the fixative penetrates deeper into tissue
  55. 55—

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Description
Histotechnology Flashcards on Histotechnology, created by Victoria Station on 20/04/2019.
Created by
Victoria Station · Apr 2019
Updated
Apr 20, 2019
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