Specimen Preparation Flashcards
7 cards from real Histology Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Specimen Preparation flashcards as text
Which statement correctly describes the difference between autolysis and putrefaction in post-mortem tissue?
Answer: Autolysis is self-digestion by endogenous enzymes; putrefaction involves bacterial decomposition
Autolysis is enzymatic self-digestion from within the cell, while putrefaction is decomposition driven by bacterial action.
A histotechnologist notices that sections from a thyroid gland have extreme shrinkage artifact. The most probable cause is:
Answer: Overly rapid alcohol dehydration causing tissue contraction
Rapid passage through high-concentration alcohols causes abrupt water loss, leading to pronounced tissue shrinkage.
For optimal immunofluorescence (IF) studies on renal biopsy, the preferred fixation and processing method is:
Answer: Michel's transport medium followed by frozen sectioning
Michel's transport medium preserves antigens for direct IF studies on fresh frozen sections without formalin cross-linking.
The 'spreading' of nuclear chromatin and 'soap bubble' cytoplasm in a tissue section is characteristic of:
Answer: Autolysis prior to fixation
Autolytic changes such as nuclear chromatin spreading and foamy cytoplasmic vacuolization occur when unfixed tissue undergoes endogenous enzymatic digestion.
Which factor most significantly affects formalin fixation penetration rate?
Answer: Specimen thickness
Formalin penetrates at approximately 1 mm/hour, so specimen thickness is the primary rate-limiting factor for complete fixation.
A tissue processed in an automated processor shows paraffin that did not infiltrate the center. The most likely reason is:
Answer: Incomplete dehydration or clearing left aqueous solvent in the center
Paraffin is water-immiscible, so any residual water or aqueous solvent from incomplete dehydration or clearing blocks paraffin infiltration.
What is the correct action when a cryostat section shows excessive ice crystal artifact obscuring cellular detail?
Answer: Ensure tissue is snap-frozen rapidly in liquid nitrogen or isopentane before cryosectioning
Slow freezing allows large ice crystals to form that rupture cells; snap-freezing in isopentane cooled by liquid nitrogen produces minimal ice crystal artifact.