L.3 Artefacts Flashcards
What are artefacts in histology?
Distortions or alterations in tissue appearance that arise during preparation, processing, or staining
Artefacts are not present in the living tissue but can interfere with diagnosis or research.
Why is it important to recognize artefacts?
They can interfere with accurate diagnosis or research by mimicking disease or obscuring tissue structures
Minimizing artefacts is crucial for accurate histological assessment.
What is autolysis?
The breakdown of cell structures by enzymes within the cells due to delayed fixation after removal from the body
Common in post-mortem samples.
What occurs during autolysis?
Loss of cellular detail and blurring of tissue architecture
It happens when tissue is not fixed promptly.
What is the role of fixation in histology?
To preserve tissue, prevent autolysis and putrefaction, and stabilize cellular components
Proper fixation is essential to avoid artefacts.
What can improper fixation create?
Artefacts
Fixed tissue is no longer in its natural state.
What is under-fixation?
Incomplete penetration of fixative leading to poorly preserved central tissue
Can result in uneven staining.
What is over-fixation?
Excessive cross-linking causing hardening and shrinking of tissue
It can compromise the integrity of the sample.
What can wrong pH or unbuffered fixatives cause?
Precipitation, acid damage, or distorted cellular appearance
The chemical environment is critical for proper fixation.
How do different fixatives affect tissue appearance?
Different fixatives can give varying morphologies
Example: Formalin vs. alcohol-based fixatives.
What can cause artefacts during collection and preparation?
Poor handling or mechanical trauma
Artefacts can result from various factors, including environmental conditions and procedural errors.
What are freezing artefacts?
Caused by sudden or unplanned freezing, forming ice crystals that rupture cells
This can occur due to unexpected death or improper storage conditions.
What can over-perfusion during necropsy lead to?
Tissue swelling or rupture
Over-perfusion can compromise the integrity of the tissue being examined.
What happens when cassettes are overfilled?
Tissues packed too tightly can be unevenly processed
This can affect the quality of the final tissue section.
What are the consequences of microtomy damage?
Tearing, folding, or chatter
Damage can result from using blunt blades, uneven cutting, or excessive pressure.
What can incorrect orientation during trimming cause?
Missing important structures or distortion
Proper orientation is critical for accurate diagnosis.
What are the potential outcomes of improper tissue orientation in cassettes?
- Missing diagnostic areas
- Sectioning through irrelevant planes
- Structural distortion in the final section
These outcomes can significantly impact diagnostic accuracy.
What is under-processing in tissue preparation?
Poor dehydration/clearing leading to soft, poorly infiltrated tissue
This can compromise the quality of histological examination.
What can over-processing result in?
Brittle, shrunken samples
Over-processing can adversely affect the structural integrity of the tissue.
What are common microtomy artefacts?
- Wrinkles
- Knife marks
- Chatter (rippled sections)
- Compression
These artefacts can hinder accurate tissue evaluation.
What can failure to dewax lead to?
Prevents proper staining
Dewaxing is a crucial step in preparing slides for staining.
What causes uneven staining?
Patchy appearance due to poor reagent flow or improper technique
Proper technique is essential for uniform staining results.
What are stain precipitates?
Dried stain drops on slides or poorly filtered reagents can leave granules
Stain precipitates can interfere with the clarity of the tissue section.
What is background staining?
Excess stain not properly washed off
Background staining can obscure important details in the tissue section.
