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40 Cards in this Set
- Front
- Back
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excessive dehydration results in |
hard brittle tissue |
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incomplete dehydration results in |
soft mushy tissue |
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dehydrating fluid- does not harden tissue, not used in staining because many dyes are not soluble in it |
isopropanol |
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dehydrating fluid that dehydrates and fixes blood smears |
methanol |
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3 universal solvents |
THF (tetrahydrofuran), dioxane, butanol |
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two xylene substitutes used as clearing agents |
aliphatic hydrocarbons, limonene |
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clearing agent-one of the best, does not harden as much as xylene, toxic |
toluene |
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clearing agent- not flammable but releases toxic phosgene gas, penetrates slower but causes less brittleness |
chloroform |
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clearing agent- toxic gas released when heated, seldom used |
carbon tetrachloride |
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clearing agent- best by old standards, no QC |
aviation gasoline |
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clearing agent- essential oil rapid but causes brittleness |
cederwood oil |
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all essential oils must be removed with ___ before paraffin |
xylene |
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melting point of routine wax is |
55-60 C |
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improper infiltation- soft and crumbling tissue = |
clearant still in tissue |
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improper infiltration- breaking up on water bath = |
wax is not penetrated throughout |
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improper filtration- difficult in ribboning= |
wax is too soft |
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3 plastic type infiltration medias |
GMA, MMA, epoxy type |
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acrylic resin that is not miscible with water but is with alcohol and solvents. used for undecaled bone, metal implants and large tissue, use titanium knife or grinding and polishing |
MMA (methyl ethacrylate) |
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plastic infiltration medium is usually used in.. |
transmission electron microtomy |
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when using NBF, first dehydration step must be ____ alcohol or less |
70% |
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P- tissue shrunken away from wax |
insufficient dehydration |
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P- specimen crumbles out of wax, only rim of wax on slide |
insufficient infiltration, or overheated paraffin causing brittle tissue |
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P- sections expand or disintegrate on water bath |
poor impregnation, or water temp too high |
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P- poor morphological detail, poor staining generally worse in center of tissue, tissue has fresh appearance |
unfixed tissue/inadequate time in fixative |
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P- section explodes on water bath, tissue in block sunken and pulled away from paraffin 24 hours later, incomplete sections usually first when cutting |
incomplete dehydration |
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P- dense muscular tissue shoes venetian blind, washboard, thick/thin |
overdehydration |
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P- incomplete sections, center of tissue affected, faint smell of alcohol, tissue sucken after hours |
inadequate clearing |
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P- tissue becomes hard and brittle, venetian blind, washboard, thick/thin |
excessive clearing |
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P- incomplete section, holes in tissue, generally the center is affected, tissue appears fresh, faint smell of clearant, block may appear soft and sections wrinkle |
inadequate infiltration |
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P- hard brittle tissue, shattered, washboard, thick/thin sections |
excessive infiltration |
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reagents that both dehydrate and clear are called |
universal solvents |
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embedding medium of choice for very hard tissue |
GMA (glycol methacrylate) |
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if infiltration paraffin is too hot, it could result in |
hard brittle tissue |
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H&E-stained sections show very unseen staining of the tissue, with poor nuclear detail. One possible cause is |
water in clearing agent |
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xylene, toluene and benzene belong to which chemical class |
hydrocarbon |
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if the clearing agent is cloudy after tissue is processed, it probably is contaminated with |
water |
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paraffin processing is not recommended for the preservation of |
enzymes |
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in the body, which solution is poionous because it is oxidized to formaldehyde |
methanol |
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two water soluble media are carbowax and |
OCT |
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two types of embedding media |
water soluble and water insoluble |
