Chapter 5 - Histotechnology Self-Assessment Workbook, 5th Edition

Which of the following is a dehydrating agent?

formalin

xylene

benzene

alcohol

alcohol

A clearing agent for use in processing tissues for paraffin embedding must be miscible with the:

fixative and paraffin

dehydrant and paraffin

fixative and dehydrant

paraffin and water

dehydrant and paraffin

Dioxane is a reagent that can be used for which two steps in processing?

dehydrating and clearing tissues

(Dioxane is a Universal Solvent - something that can be used for both dehydrating and clearing tissues)

All of the following reagents can be used to dehydrate tissue EXCEPT:

benzene

absolute alcohol

dioxane

acetone

benzene

Most commonly, the paraffin used for embedding tissues is kept at approximately what temperature?

60*C

A disadvantage of the use of dioxane (a universal solvent) in processing tissues is that it is:

toxic

likely to harden tissues

not miscible with water

explosive

toxic

The chief objection to the use of xylene as a clearing agent for processing tissues is that xylene is:

likely to harden tissue

hydroscopic

only slightly miscible with paraffin

the most volatile of the hydrocarbons

likely to harden tissue

A good paraffin for routine use is one with a melting point within what range?

55-58*C

All of the following chemicals are clearing agents EXCEPT:

chloroform

dioxane

ethanol

xylene

ethanol

Overheating of the paraffin used for embedding may cause:

air bubbles in the block

cracking of the block

tissue to adhere to the cassette

poor infiltration

cracking of the block

One advantage of the paraffin technique is that:

hard objects cut easily

there is practically no tissue distortion

serial sections are easy to obtain

microtomy artifacts are uncommon

serial sections are easy to obtain

When cutting paraffin-embedded tissues, if the tissue seems hard and brittle, one source of trouble is likely to be:

inadequate fixation

incomplete dehydration

overheated paraffin

poor infiltration

overheated paraffin

The process of removing water from tissue is called what?

dehydration

Reagents that both clear and dehydrate are called what?

universal solvents

Paraffin that is considered soft:

is required for use with high room temperature

is best for embedding and sectioning hard tissues

has a melting point of ~56*C to 58*C

is most useful when thick sections are desired

is most useful when thick sections are desired

When used for clearing, cedarwood oil must be followed by:

alcohol

xylene

a universal solvent

paraffin

xylenePa

Paraffin is cooled as rapidly as possible after embedding tissue to:

prevent the formation of large crystals

remove air bubbles from the paraffin

lower the melting point of the paraffin

aid infiltration into the tissue

prevent the formation of large crystals

A small laboratory with a variable daily process workload should change reagents how often?

based on a predetermined threshold

Benzene is used as:

dehydrant

clearing

infiltration/embedding

clearing

Paraffin is used as:

dehydrant

clearing

infiltration/embedding

infiltration/embedding

Limonene derivatives are used as:

dehydrant

clearing

infiltration/embedding

clearing

Dioxane is used as:

dehydrant

clearing

infiltration/embedding

dehydrant and clearing

(universal solvent)

Agar is used as:

dehydrant

clearing

infiltration/embedding

infiltration/embedding

Chloroform is used as:

dehydrant

clearing

infiltration/embedding

clearing

Ethyl alcohol is used as:

dehydrant

clearing

infiltration/embedding

dehydrant

Gelatin is used as:

dehydrant

clearing

infiltration/embedding

infiltration/embedding

Xylene is used as:

dehydrant

clearing

infiltration/embedding

clearing

Isopropanol is used as:

dehydrant

clearing

infiltration/embedding

dehydrant

Butyl alcohol is used as:

dehydrant

clearing

infiltration/embedding

dehydrant

Tetrahydrofuran is used as:

dehydrant

clearing

infiltration/embedding

dehydrant and clearing

(universal solvent)

Toluene is used as:

dehydrant

clearing

infiltration/embedding

clearing

Aliphatic hydrocarbons are used as:

dehydrant

clearing

infiltration/embedding

clearing

The use of 2 embedding mediums, such as agar and paraffin, is known as duel embedding. True or False?

False

(actually called “double embedding”)

A sponge artifact is created when the tissue is placed between 2 dry sponges for processing. True or False?

True

Frozen sections are specified for processing tissue for the demonstration of most enzymes. True or False?

True

Overheating of the paraffin used for infiltration will cause shrinkage and overhardening of the tissue. True or False?

True

Skin sections are embedded so that the epithelial surface is face down in the block. True or False?

False