Midterms

• What are the 12 steps outlined in the study material?

  1. Numbering
  2. Fixation
  3. Dehydration
  4. Clearing
  5. Infiltration
  6. Embedding
  7. Blocking
  8. Trimming
  9. Sectioning

  10. Staining

  11. Mounting

  12. Labeling
• Who is the author of the study material?

  NEILDINE V. BARCENAS, RMT, MD
• Why is numbering considered the first and most important step?

  It helps in maintaining a logbook for tracking specimens.
• What is an example of a logbook entry for numbering?

  Histopath-2023-0001
• What should be indicated in the numbering process?

  The year should be indicated.
• What is the purpose of using a pencil in the numbering process?

  Pencil is used to avoid interference from stains that pens may cause.
• What is the recommended specimen size for processing?

  3x2 cm and 3-5 mm thick
• What can be added to small tissues during processing?

  1% eosin can be added.
• What is the required angle for tissue slices at the surface of the organ?

  Right angle
• What is the size requirement for specimens in Electron Microscopy (EM)?

  Specimens should be 1 mm³.
• What is the primary goal of fixation?

  To preserve cell and tissue constituents in a condition identical to that during life.
• What are the two important goals of fixation?

  Preserve morphology and chemical integrity of the cell, and harden tissue for further handling.
• What is additive fixation?

  It involves the formation of cross-links or complexes in the tissue.
• Name an example of an additive fixative.

  Formalin
• What is non-additive fixation?

  It does not incorporate into the tissue and removes bound water.
• What is an example of a non-additive fixative?

  Alcohol fixatives
• What pH range is ideal for fixation?

  pH 6-8
• What are the general effects of fixatives?

  They harden tissue, make cells resistant to damage, inhibit bacterial decomposition, and increase optical differentiation.
• What is the traditional temperature for fixation?

  Room temperature
• What is the temperature for rapid fixation?

  60°C
• What temperature is used for Electron Microscopy and histochemical fixation?

  0-4°C
• What is the fixation temperature for tissues with tuberculosis?

  100°C
• What is the recommended thickness for specimens in Electron Microscopy?

  1. 2 mm².
• What is the recommended thickness for specimens in Light Microscopy?

  2 cm².
• What is the exception for tissue thickness in edematous lung tissue?

  It can be 1-2 cm thick.
• How should brain tissue be fixed?

  It should be suspended or submerged whole in fixation solution.
• What is the recommended fixative for brain tissue?

  10% buffered formalin for 2-3 weeks.
• How should large and solid tissues like the uterus be prepared for fixation?

  They should be opened and sliced into tiny sizes.
• What is the ideal concentration of formalin for fixation?

  10%
• What is the osmolality requirement for fixation solutions?

  Slightly hypertonic solution of 400-450 mOsm.
• What is the recommended concentration of glutaraldehyde for small tissue fragments?

  1. 5%
• What is the primary duration for primary fixation in buffered formalin?

  1. 6 hours.
• What is the ideal concentration of glutaraldehyde for immunoelectron microscopy?

  0.25%
• What is the fixation duration for Electron Microscopy?

  3 hours, then placed in holding buffer.
• Why is speed important in fixation?

  To prevent autolysis and putrefaction.
• What is the fixative volume for osmium tetroxide?

  1. 10 times that of the tissue.
• What is the rate of penetration for fixatives?

  1 mm/hour.
• What is the volume requirement for museum preparations?

  Not less than 50 times for long-term storage.
• What is the recommended volume of fixative relative to the tissue?

  10-20 times that of the tissue.
• What factors influence the duration of fixation?

  It depends on the tissue structure.