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128 Cards in this Set
- Front
- Back
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During microtomy, it is noted that many of the tissues to be examined seem very hard and shrunken. Of the following, the most likely explanation for this problem is that the:
a) infiltrating paraffin is too hot b) processing reagents need changing c) pH of the fixative was incorrect d) clearing agent is contaminated with water |
a) infiltrating paraffin is too hot
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Decalcification of small specimens can be acheived by fixation in:
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Zenker solution
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A major disadvantage of aliphatic clearing agents is that they:
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are incompatible with some mounting media
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Which of the following is MOST likely to cause sensitization with prolonged use?
a) cedarwood oil b) xylene c) aliphatic hydrocarbons d) limonene |
d) limonene
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To speed up the laboratory's processing of all surgical tissues, the temperature of all fixation, dehydration, and clearing steps has been set at 45⁰C. This will most likely result in:
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overprocessed biopsy tissue
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Limonene functions as a(n):
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clearing agent only
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One advantage of aliphatic hydrocarbons is that they:
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are low in toxicity and sensitization
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A disadvantage of using heat at all stations of the enclosed tissue processor is that it will:
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harden some tissues
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Dehydration refers to the removal of:
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water
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Which decalcification method may cause burning of the specimen?
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electrolytic
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Which of the following clearing agents is NOT flammable?
a) benzene b) chloroform c) toluene d) xylene |
chloroform
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Which of the following groups of reagents may be used for dehydration?
a) ethanol, limonene, and tetrahydrofuran b) methanol, ethanol, and limonene c) dioxane, methanol, and toluene d) dioxene, methanol, and ethanol |
d) dioxene, methanol, and ethanol
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Which of the following is routinely used in electron microscopy?
a) agar b) celloidin c) ester wax d) resin |
d) resin
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A clearing agent must be miscible with:
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dehydrants and infiltrating media
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Which of the following is a chelating agent used for decalcification?
a) ethylenediaminetetraacetic acid b) HCl c) trichloracetic acid d) phenol |
a) ethylenediaminetetraacetic acid
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The alcohols on the automated tissue processor should be changed on a regular basis because:
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the alcohols can absorb moisture and become dilute
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After completion of decalcification, the specimen should be:
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washed in water
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Schedule A:
formol-alcohol: 2 hrs 95% OH: 1 hr 95% OH: 1hr Abs. OH: 1hr Abs. OH: 1hr Xylene: 1hr Xylene: 1hr Paraffin: 1hr Paraffin: 1hr Paraffin: 1hr Paraffin: 20min Schedule B: 80% alcohol: 20min 80% alcohol: 20min 95% alcohol: 20min 95% alcohol: 20min Abs. alcohol: 20min Abs. alcohol: 20min Xylene: 20min Xylene: 20min Paraffin: 20min Paraffin: 20min Schedule C: 80% alcohol: 8hrs 95% alcohol: 4hrs 95% alcohol: 4hrs abs. alcohol: 4hrs abs. alcohol: 4hrs chloroform: 1hr chloroform: 1hr chloroform: 1hr paraffin: 2hrs paraffin: 2hrs paraffin: 2hrs Which of the processing schedules above should be used to process fixed routine surgical tissue in a closed processor? |
Schedule A
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Ethanol functions as a(n):
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dehydrating agent
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Schedule A:
formol-alcohol: 2 hrs 95% OH: 1 hr 95% OH: 1hr Abs. OH: 1hr Abs. OH: 1hr Xylene: 1hr Xylene: 1hr Paraffin: 1hr Paraffin: 1hr Paraffin: 1hr Paraffin: 20min Schedule B: 80% alcohol: 20min 80% alcohol: 20min 95% alcohol: 20min 95% alcohol: 20min Abs. alcohol: 20min Abs. alcohol: 20min Xylene: 20min Xylene: 20min Paraffin: 20min Paraffin: 20min Schedule C: 80% alcohol: 8hrs 95% alcohol: 4hrs 95% alcohol: 4hrs abs. alcohol: 4hrs abs. alcohol: 4hrs chloroform: 1hr chloroform: 1hr chloroform: 1hr paraffin: 2hrs paraffin: 2hrs paraffin: 2hrs Which of the processing schedules shown above should be used to process a fixed-needle biopsy of the liver using a closed tissue processor? |
Schedule B
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Butyl alcohol is recommended as a dehydrant for:
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plant tissue
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Isopropanol functions as a(n):
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dehydrant agent only
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Dehydrating tissues in graded alcohols of increasing concentrations is superior to using absolute alcohol only because it will:
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cause less distortion of the tissue
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When preparing tissues for electron microscopy, the degree of dehydration should be:
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complete
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The best method of preparing tissue for enzyme demonstration is:
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unfixed frozen sections
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Glycol methacrylate functions as a(n):
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infiltrating medium
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Fat remains in the tissue following infiltration with:
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Carbowax
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Methanol functions as a(n):
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dehydrating agent only
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The most rapid-freezing tissue is the result of using:
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liquid nitrogen/isopentene
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The amount of time a specimen needs to remain in decalcifying solution is NOT influenced by the:
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processing schedule
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Tissue will NOT be damaged by extended periods of time in:
a) acetone b) benzene c) cedarwood oil d) absolute ethanol |
c) cedarwood oil
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Tissue must be dehydrated before placing it in:
a) agar b) Carbowax c) Epon d) gelatin |
c) Epon
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Which of the following chemicals can be used to indicate the presence of water in alcohol?
a) copper sulfite b) copper sulfate c) sodium sulfite d) sodium sulfate |
b) copper sulfate
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The ideal thickness of specimens to be decalcified is:
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3 to 4nm
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Paraffin processing is contraindicated for the subsequent demonstration of:
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enzymes
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Which of the following reagents is miscible with water, alcohol, hydrocarbons, and paraffin?
a) acetone b) cedarwood oil c) dioxane d) xylene |
c) dioxane
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When using epoxy resin during processing, which of the following is typically used as the transitional fluid between alcohol and the epoxy resin?
a) acetone b) chloroform c) dioxane d) propylene oxide |
d) propylene oxide
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80% OH: 20min
80% OH: 20min 95% OH: 20min 95% OH: 20min Abs. OH: 20min Abs. OH: 20min Abs. OH: 20min Xylene: 20min Xylene: 20min Paraffin: 20min Paraffin: 20min Paraffin: 2hrs Refer to the schedule above. If processing starts at noon, in which solution will the tissue be at 1:45pm? |
second abs. alcohol
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Prolonged dehydration in higher grades of alcohol will render a specimen:
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hard
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For adequate clearing in xylene during routine processing, tissue should have a maximum thickness of:
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3 to 4nm
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Cedarwood oil functions as a(n):
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clearing agent only
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Processing of delicate tissues (eg: embryonic tissues) should be started in what concentration of alcohol?
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30%
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Chloroform functions as a:
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clearing agent only
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The effect of overdecalcification is most noticeable in the staining of:
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nuclei
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Which of the following is considered to always be the best dehydrant?
a) acetone b) ethanol c) isopropanol d) methanol |
b) ethanol
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All of the following are methods for checking the completeness of decalcification EXCEPT:
a) chemical b) electrolytic c) mechanical d) radiographic |
b) electrolytic
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Acid solutions soften bone tissue by removing which of the following salts?
a) calcium b) lithium c) potassium d) sodium |
a) calcium
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A process that can preserve enzymes and prevent the loss of some cellular constituents is:
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freeze-drying
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If the clearing agent is cloudy, it may be contaminated with:
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water
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Dioxane functions as a:
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universal solvent
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Which of the following gases is released during decalcification?
a) ammonia b) carbon dioxide c) nitrous oxide d) oxygen |
carbon dioxide
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Epon functions as a:
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infiltrating medium
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Tetrahydrofuran functions as a:
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universal solvent
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During processing for electron microscopy, specimen dehydration using absolute ethanol should be carried out in capped vials because when specimen are left open there is a tendency for:
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absorption of atmospheric moisture
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The time needed for infiltration of paraffin into a tissue specimen is dependent upon all of the following EXCEPT the:
a) fixative used b) thickness of the specimen c) tissue type d) use of vacuum |
fixative used
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Xylene functions as a:
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clearing agent only
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To offset the hydrolysis of nucleic acids caused by decalcifying agents, bone marrow biopsy specimens are sometimes fixed in:
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Zenker solution
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Which of the following can be used to hold exudate or friable tissues in place for processing?
a) agar b) celloidin c) paraffin d) resin |
a) agar
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The longest time that tissue can remain in cedarwood oil without any apparent harm is:
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months
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Decalcification occurs with all of the following methods EXCEPT:
a) simple acid b) radiographic c) chelation d) ion-exchange |
b) radiographic
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Which of the following is soluble in various fat solvents?
a) agar b) Carbowax c) gelatin d) paraffin |
d) paraffin
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The process of saturating tissue with the medium that will be used for embedding is called:
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infiltration
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Toluene functions as a:
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clearing agent only
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Of the reagents listed below, the best substitute for ethanol for processing tissues is:
a) dioxane b) butanol c) isopropanol d) methanol |
c) isopropanol
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80% alcohol: 8hrs
95% alcohol: 4hrs 95% alcohol: 4hrs Abs. alcohol: 4hrs Abs. alcohol: 4hrs Chloroform: 1hr Chloroform: 1hr Chloroform: 1hr Paraffin: 2hrs Paraffin: 2hrs Paraffin: 2hrs (in vacuum) If processing started at 8am Monday, at what time on Tuesday will the tissue be ready to embed? |
5pm on Tuesday
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Which clearing agent must be removed with volatile hydrocarbon prior to impregnation?
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cedarwood oil
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Which of the following must one do when using an essential oil as a clearing agent?
a) avoid the use of ethyl alcohol b) remove the oil with xylene c) avoid exposure to heat d) avoid lengthy exposure |
b) remove the oil with xylene
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Slow freezing of tissues prior to sectioning will most likely:
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yield sections showing tissues disruption
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An open tissue processor malfunctions, advancing tissue one step further than normal at the end of processing and placing the tissue in fixative. The best course of action is to:
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treat the tissue with absolute ethanol, xylene and paraffin
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Determining the end-point of decalcification is very important because:
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overdecalcification results in destruction of cell structure
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Paraffin with a melting point of 55⁰C is used for impregnation and embedding. The temperature of the paraffin containers should be regulated at approximately:
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58⁰C
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For successful impregnation of tissue, the time needed for infiltration with paraffin depends on the:
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thickness and texture of the tissue
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Dioxane is a reagent that can be used
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for both dehydrating and clearing tissues
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The chief objection to the use of xylene as a clearing agent for processing tissues is that xylene
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likely to harden tissue
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Overheating of the paraffin used to embed may cause
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cracking of the block
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Paraffin is cooled down as fast as possible to prevent
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formation of large ice crystals
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the dehydration and clearing steps can be omitted when using
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water soluble wax
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Should bone sections be embedded parallel to the long axis of the block
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NO it should be diagonal
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Formic and Nitric acid are both used for
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Decalcifying
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Nitric acid impairs
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staining reactions
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After how many hours will nitric acid damage tissue
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48
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Is formic or Nitric acid used with ion exchange resins
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Formic
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Tetrahydrofuran is what type of solvent
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universal
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Will xylene and tetrahydrofuran clear tissue for infiltration
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yes
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chloroform and cedar wood oil are both
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clearing agents
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Does chloroform make tissue transparent
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NO
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When undecalcified bone is to be embedded it must be embedded in
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plastics/resins
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What is used to check end point decalcification
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ammonium oxalate which precips the phosphates.
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Define: Dehydration
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the removal of water
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Define: Clearing
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process of replacing the alcohol (dehydrating agent) with a reagent that is miscible with paraffin. Most leave the tissue transparent
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Define: Infiltration
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permeation, as in paraffin permeating (spreading or flowing throughout) tissue; impregnation
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Define: Embedding
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also referred to as casting or blocking, involves enclosing the tissue in the infiltration medium used for processing and then allowing the medium to solidify
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Define: Universal solvent
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Chemical reagent that acan be used for both the ehydrating and clearing steps in tissue processing. Dioxane, tertiary butanol, and tetrahydrofuran
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Define: Essential oil
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natural substance you can use for a clearing agent (instead of Xylene) ie. Eucalyptus oil, peanut oil
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Define: Carbowax
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a water soluable wax that will not infiltrate fatty tissue
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Define: Cross-section
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cutting a specimen to show the entire view
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Define: Decalcification
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The process of removing calcium form bone or tissue
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Define: Ion exchange
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used for decalcification. Method includes using an ion gradient and electrons
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Define: Chelating agent
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organic compounds that have the property of binding certain metals
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Define: Miscible
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capable of mixing or being mixed
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A clearing agent for use in processing tissues for paraffin embedding must be miscible with the...
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dehydrant and paraffin
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Which of the following is a dehdrating agent...
a) formalin b) xylene c) benzene d) alcohol |
d) alcohol
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Dioxane is a reagent that can be used...
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for both dehydrating and clearing tissues
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A reagent that CANNOT be used for dehydrating tissue is...
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benzene
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Most commonly, the paraffin used for embedding tissues is kept at approximately...
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60 degrees C
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A disadvantage of the use of dioxane in processing tissues is that it is...
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toxic
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The chief objection to the use of xylene as a clearing agent for processing tissues is that xylene is...
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likely to harden tissue
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A good paraffin for routine use is one with a melting point of...
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55-58 degrees
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Which of the following chemicals is NOT a clearing agent...
a) chloroform b) dioxane c) ethanol d) xylene |
c) ethanol
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Overheating of the paraffin used to embed may cause...
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cracking of the block
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One advantage of the paraffin technique is that...
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serial sections are easy to obtain
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When cutting paraffin embedded tissues, if the tissue seems hard and brittle, one source of trouble is likely to be...
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overheated paraffin
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The process of removing water from tissue is called...
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dehydration
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Reagents that both clear and dehydrate are called...
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universal solvents
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Paraffin that is considered soft...
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is most useful when thick sections are desired
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When used for clearing, cedar wood oil must be followed by...
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xylene
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Paraffin is cooled as rapidly as possible after embedding tissue in order to...
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prevent the formation of large crystals
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the dehydration and clearing steps can be omitted when using...
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water soluble wax
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During microtomy it is noted that most of the tissue is very hard and shrunken. One of the first things to check to prevent its happening in the future is the...
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temperature of the infiltrating paraffin
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H and E stained sections show very uneven staining of the tissue, with poor nuclear detail. One possible cause is...
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water in the clearing agent
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Phosphate-buffered formaldehyde is used in the first two stations of the closed processor. A white precipitate is forming in the processor tubing, and the tissue is more difficult to cut than usual. One of the first things to check to correct the problem is...
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percent alcohol used as the first dehydrant
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At microtomy, formalin-fixed, paraffin-embedded kidney sections are soft and mushy. This is most likely due to...
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inadequate dehydration and clearing
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Aqueous unbuffered zinc formalin is used at the first stage on the closed processor, followed by phosphate-buffered formalin and 65% alcohol. It is noted that a white precipitate is most likely due to...
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the formation of zinc phosphate
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Tissue is processed with the following reagents...
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-10% neutral-buffered formalin for 2 changes
-65% alcohol for 1 change -95% alcohol for 2 changes -100% alcohol for 2 changes -aliphatic hydrocarbon for 2 changes -paraffin for 3 changes |
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The tissue does not seem to be well cleared and infiltrated. This problem might be solved by adding...
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an aliphatic hydrocarbon and deleting one 95% alcohol
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Tissue is processed on an open processor with the following reagents...
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-10% neutral-buffered formalin for 2 changes
-65% alcohol for 1 change -95% alcohol for 1 change -100% alcohol for 2 changes -aliphatic hydrocarbon for 3 changes -paraffin for 3 changes |
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At microtomy, many of the tissues are soft and mushy. One cause of the problem might be...
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high relative humidity in processor area
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Many of the zinc formalin-fixed biopsy specimens are hard and brittle and show microscopic chatter. this will result if the specimens are...
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processed incorrectly
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