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44 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Steps of processing |
Fixation Dehydration Clearing Infiltration |
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Reason for dehydration |
Remove water from tissue Enables tissue to be embedded by paraffin |
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Reason for clearing |
Removing alcohol from dehydration Makes tissue susceptible for infiltration |
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Reason for infiltration |
Prepping tissue for embedding medium (paraffin) Allows for easy microtomy |
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Define Miscibility |
A substance that can form a solution |
Alcohol & water = yes Oil & water = no |
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Open processors |
Tissue is transferred from one solution to the next |
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Closed processor |
Solutions pumped in and out of tissue |
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Maintenance & QC for processors include... |
Monitor reagents (correct order, top off, change when needed) Monitor paraffin temperatures (above melting point) |
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Excessive dehydration causes |
Hard/brittle tissue |
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Incomplete dehydration causes |
Soft/mushy tissue, clearing agent won’t act properly |
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Dehydrating agents include: |
Ethanol Methanol Isopropanol Butanol Acetone |
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Universal Solvents are: |
Reagents that can perform both dehydrating and clearing steps |
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The 3 Universal reagents are: |
Dioxane Tertiary butanol Tetrahydrofuran |
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Clearing agents include: |
Xylene - Limonene, Alkanes Toluene Benzene Chloroform Essential oils Acetone |
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Infiltrating mediums include: |
Paraffin Water soluble waxes (carbowax) Celloidin Plastics Agar & gelatin |
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Paraffin additives include: |
Beeswax Rubber Other waxes Plastics |
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Factors that can affect processing include: |
Agitation Heat (high temps) Viscosity Vacuum pressure Clogged processing lines |
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Which alcohol is commonly used for blood smears? |
Methanol (Methyl Alcohol) |
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Most common alcohol used forndehydration |
Ethanol |
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Inadequate clearing causes: |
Inadequate infiltration Soft mushy tissue |
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Prolonged clearing causes: |
Hard / brittle tissue Denaturation if tissue |
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Most common clearing agent is |
Xylene |
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Xylene substitutes include |
Limonene reagents Alkanes |
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What is the function of infiltration? |
Support tissue so the cells and structures are in their proper relationship during microtomy |
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Most common infiltration medium: |
Paraffin wax |
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Effects of a higher melting point with paraffin wax: |
Increases hardness, supports, easier to cut tin sections |
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Effects of lower melting point |
Softer, less support, easier to ribbon |
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What type of artifact is shown? |
Over dehydration causing chatter |
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What reaction is being shown? |
Improper heat/processing caused hazy blue nuclei |
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What problem is shown above? |
Uneven staining - caused by contaminated clearing or infiltration reagent |
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What is wrong with this tissue? |
Cross hatching artifact / Sponge artifacts |
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What causes this issue? |
Incomplete fixation before grossing |
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What problem is present with this specimen |
H&E stain of overdecalcified bone |
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What is shown above? |
Under Decalcification in H&E bone |
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What is shown above? |
Proper decalcified bone in H&E stain |
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What is the typical melting point for paraffin wax? |
55-58°C |
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Precautions when using zinc formalin: |
Zinc salts can clog processing lines |
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Inadequate fixation causes... |
Cell shrinkage |
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Inadequate dehydration causes... |
Mushy tissue |
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Excessive dehydration causes... |
Hard/brittle tissue Cell shrinkage |
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Inadequate clearing causes... |
Soft & mushy tissue |
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Excessive clearing causes... |
Hard / brittle tissue Denaturation of tissue |
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QC for processing |
Check fluid levels Document changes Document loads/unloads/cleaned process Clean cycle after each run Recycle reagents |
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How to prevent cell shrinkage |
Complete fixation Complete submerging |
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