HISTOPATH LAB DEHYDRATION

Question 1

Acetone can be used as a fixative and
dehydrating agent

Answer 1

TRUE

Question 2

Acetone can be used as a fixative and
dehydrating agent

Answer 2

TRUE

Question 3

Automates tissue preparation for histological examination.

Answer 3

tissue processor

Question 4

Removal of calcium from the tissue

Answer 4

decalcification

Question 5

Removal of calcium from the tissue

Answer 5

decalcification

Question 6

FIXATION IS DONE AFTER
DECALCIFICATION.

Answer 6

TRUE

Question 7

Removal of water.
○ Gradually remove the water by replacing
water with a dehydrating agent (i.e ethyl
alcohol).

Answer 7

DEHYDRATION

Question 8

Removal of dehydrating agent and
preparation of tissue for the infiltrating agent.

Answer 8

CLEARING

Question 9

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.

It utilize series of
alcohol as dehydrating fluid.

Answer 9

PARAFFIN WAX METHOD

Question 10

MOST ALCOHOLS AND PARAFFIN ARE NOT MISCIBLE

Answer 10

TRUE

Question 11

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

Answer 11

ETHANOL

Question 12

Characteristics: clear, colorless,
flammable liquid

Answer 12

ETHANOL

Question 13

Advantages: fast-acting, mixes
with water and many organic
solvents, penetrates tissue easily,
not poisonous and expensive.

Answer 13

ethanol

Question 14

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

Answer 14

METHANOL

Question 15

It is utilized in plant and animal
microtechniques.

Answer 15

BUTANOL

Question 16

producing less shrinkage and
hardening than ethanol.

Answer 16

BUTANOL

Question 17

Disadvantage: slow dehydrating
agent thus, it is not suitable for
rapid tissue processing.

Answer 17

BUTANOL

Question 18

The strength of initial alcohol required in each
concentration will depend upon the size, and nature
of the tissue and fixative used.

Answer 18

TRUE

Question 19

Concentrated alcohols produce shrinkage
and make the tissue hard, brittle and
difficult to cut. Do not penetrate the deeper
parts.

Answer 19

TRUE

Question 20

Prolonged storage in lower concentrations
(below 70%) tends to macerate the tissue.

Answer 20

TRUE

Question 21

Serves as an indicator
that will accelerate (removes water from the
dehydrating fluid) and insure complete dehydration.

Answer 21

anhydrous coppe sulfate

Question 22

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

Answer 22

acetone

Question 23

Cheap, rapid-acting dehydrating agent
which dehydrates in1⁄2 to 2 hours.
○ More miscible when epoxy resins than
alcohol.

Answer 23

ACETONE

Question 24

Highly flammable.
○ Penetrates tissues poorly.
○ Causes brittleness (tissues placed for
prolonged period of time).
○ Most lipids are removed from tissues.
○ Extremely volatize and inflammable (limited
to small pieces of tissue).

Answer 24

ACETONE

Question 25

excellent dehydrating and clearing agent.

Answer 25

dioxane
diethylene dioxide

Question 26

Readily miscible in water, melted paraffin, alcohol and
xylol

Answer 26

dioxane

Question 27

Tissues can be left in this reagent for long
period of time without affecting the
consistency or staining properties of the
specimen.

Answer 27

dioxane

Question 28

It should not be used routinely. The laboratory room
should be properly ventilated, and all residues should
be washed down in the sink.
● It should not be recycled as the risk of creating
explosive peroxides increases greatly.

Answer 28

DIOXANE

Question 29

Tissues which have been treated with a chromate
fixative, e.g. Regaud’s or Moller’s fluid, should be
thoroughly washed in running tap water prior to
treatment with dioxane in order to remove the
chromate

Answer 29

CHROMATE FIXATIVE = REGAUDS

Question 30

The tissues is wrapped in a gauze bag and suspended in a bottle containing dioxane and a little anhydrous calcium oxide.

● Water displaced from the tissues by dioxane and in
turn absorbed by calcium oxide or quicklime.

● Dehydration period range from 3-24 hours.

Answer 30

WEISEBERGS METHOD - 3 to 24 hours

Question 31

Cellosolve dehydrates rapidly.
○ Stored in it for months without producing
hardening or distortion.

Answer 31

CELLOSOLVE

Question 32

Combustible at 110-120 °F.
■ It is very combustible!
○ Toxic.

Answer 32

cellosolve

Question 33

If cannot be avoided, propylene based glycol ether
should be used instead of ethylene based glycol
ethers.

Answer 33

TRUE
PROPYLENE

Question 34

Removes water very readily and produces very little
distortion and hardening.

Answer 34

TRIETHYL PHOSPHATE

Question 35

Used to dehydrate sections and smears following
certain stains

Answer 35

TRIETHYL PHOSPHATE

Question 36

Both dehydrates and clears tissues.
● Dissolve many substances including fats.

Answer 36

TETRAHYDROFURAN

Question 37

Miscible with lower alcohols, ether, chloroforms,
acetone, benzene.
● May be used for demixing, clearing and dehydrating
paraffin section.
● Most staining procedures give improved results with
_________

Answer 37

TETRAHYDROFURAN

Question 38

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

Answer 38

TRUE

Question 39

To ensure that the final bath of the alcohol containing
the absolute alcohol or ethanol is free of water, a layer
of Anhydrous copper sulfate which should be approx.
________ thick, covered by filter paper to prevent the
contamination, is employed in a dehydrating vessel.

● Turns ______ if alcohol gets diluted.

Answer 39

2x2x5 cm thick

TURNS BLUE

Question 40

Dehydration can be done/processed automatically
in HP

Answer 40

TRUE