02 Dehydration

Question 1

pre-eminent type of tissue processing treatment considered to be the most suitable for routine preparation, sectioning, staining, and subsequent storage of large tissue samples

Answer 1

Paraffin wax method

Question 2

paraffin wax method uses a series of ___ as dehydrating fluid

Answer 2

alcohol

Question 3

the first step in tissue processing by which the intercellular and extracellular water from the tissue are removed after fixation and prior to wax infiltration

Answer 3

dehydration

Question 4

solvents utilized in the removal of water

Answer 4

dehydrating agents/dehydrants

Question 5

the removal of water from aqueaous-fixed tissue

Answer 5

dehydration

Question 6

since most alcohols and paraffin are not miscible, another step, known as ___ is introduced

Answer 6

clearing

Question 7

T/F: a dehydrating solution should evaporate very fast

Answer 7

F

Question 8

It is important for a dehydrating solution to be able to dehydrate ___ tissues

Answer 8

fatty

Question 9

T/F: a dehydrating solution should not harden tissues excessively and should remove stains

Answer 9

F (should NOT REMOVE stains)

Question 10

dehydrating agent:

recommended for routine dehydration of tissues and considered the best dehydrating agent

Answer 10

ethyl alcohol

Question 11

dehydrating agent:

clear, colorless, flammable fluid

Answer 11

ethyl alcohol

Question 12

dehydrating agent:

primarily used for blood and tissue films, and for smear preparations

Answer 12

methyl alcohol

Question 13

T/F: methanol is toxic to the body

Answer 13

T

Question 14

T/F: ethanol is not poisonous

Answer 14

T

Question 15

dehydrating agent:

utilized in plant and animal micro-techniques

Answer 15

butyl alcohol

Question 16

dehydrating agent:

slow dehydrating agent producing less shrinkage that hardens less than ethanol

Answer 16

butyl alcohol

Question 17

dehydrating agent:

not suitable for rapid tissue processing

Answer 17

butyl alcohol

Question 18

in dehydrating, ___ (descending/ascending) concentrations of alcohol is used

Answer 18

ascending

Question 19

factors affecting the strength of initial alcohol required in dehydration

Answer 19

size
nature of tissue
fixative used

Question 20

smaller and more delicate tissues require ___ (higher/lower) concentration and ___ (longer/shorter) intervals between ascending grades of alcohol in dehydration

Answer 20

lower
shorter

Question 21

the tissue may be stored in ___ alcohol but not for longer periods of time

Answer 21

70-80

Question 22

prolonged storage in lower concentration of alcohol tends to ___ the tissue, while higher concentration may interfere with the ___ properties

Answer 22

macerate
staining

Question 23

the dehydration time may be hastened at ___C

Answer 23

37C

Question 24

serves as an indicator that will accelerate and insure complete dehydration

Answer 24

anhydrous copper sulfate

Question 25

dehydrating agent:

clear, colorless fluid that mixes with water, ethanol, and most organic solvent

Answer 25

acetone

Question 26

dehydrating agent:

cheap, rapid-acting dehydrating agent which dehydrates in 1/2 to 2 hours

Answer 26

acetone

Question 27

T/F: acetone is more miscible with epoxy resins than alcohol

Answer 27

T

Question 28

dehydrating agent:

an excellent dehydrating and clearing agent that is readily miscible in water, melted paraffin, alcohol, and xylol

Answer 28

dioxane

Question 29

T/F: one of the major disadvantages of dioxane is that is shrinks that tissue

Answer 29

F (it produces less tissue shrinkage)

Question 30

dehydrating agent:

tissues may be placed directly into the solution after washing out

Answer 30

dioxane

Question 31

dehydrating agent:

makes the tissue brittle with prolonged exposure

Answer 31

acetone

Question 32

T/F: one of the major disadvantages of acetone is that is shrinks that tissue

Answer 32

T

Question 33

T/F: acetone is not recommended for routine dehydration purposes

Answer 33

T

Question 34

dehydrating agent:

tissue sections tend to ribbon poorly

Answer 34

dioxane

Question 35

dehydrating agent:

produces highly toxic vapor

Answer 35

dioxane

Question 36

dehydrating agent:

should not be used routinely; the laboratory room must be properly ventilated and all residues should be washed down in the sink

Answer 36

dioxane

Question 37

in this dehydration method, the tissue is wrapped in a gauze bag and suspended in a bottle containing dioxane and a little anhydrous calcium oxide

Answer 37

Weiseberg’s method

Question 38

in Weiseberg’s method, the dehydration period range is ___

Answer 38

3-24 hrs

Question 39

in using dioxane as a dehydrating agent, tissues treated with which reagent should be thoroughly washed in running tap water prior to treatment

Answer 39

chromate fixative (Regaud’s or Moller’s fluid)

Question 40

dehydrating agent:

dehydrates rapidly; may be stored for months without producing hardening or distortion

Answer 40

cellosolve

Question 41

cellosolve is combustible at what temperature?

Answer 41

110-120F

Question 42

in using cellosolve, ___-based glycol ether should be used instead of ethylene-based glycol ethers

Answer 42

propylene

Question 43

dehydrating agent:

removes water very readily and produces very little distortion and hardening

Answer 43

triethyl phosphate

Question 44

dehydrating agent:

used to dehydrate sections and smears following certain stains

Answer 44

triethyl phosphate

Question 45

T/F: triethyl phosphate produces minimum shrinkage

Answer 45

T

Question 46

dehydrating agent:

can also be used for demixing, clearing, and dehydrating paraffin section

Answer 46

tetrahydrofuran (THF)

Question 47

dehydrating agent:

most staining procedures give improved results

Answer 47

tetrahydrofuran (THF)

Question 48

for soft tissues like an embryo, the first stage of ___ alcohol is used followed by a graded treatment of the alcohol to prevent tissue shrinkage

Answer 48

50%

Question 49

tissues fixed in ___ fluid are transferred to 90% alcohol because lower grades of alcohol may cause swelling of the fibrous tissues

Answer 49

Susa

Question 50

in quality check, a layer of anhydrous copper sulfate should be approximately ___cm thick, should prevent the contamination; alcohol would turn ___ if it gets diluted

Answer 50

2-2.5
blue

Question 51

dehydrating agent:

causes non-toxic but offensive odor

Answer 51

tetrahydrofuran