Clearing Flashcards

1
Q

It can clear 70% alc without excessive tissue shrinkage and hardening

A

Aniline oil

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3
Q

True or false:

Viscosity has no effect in the speed of penetration of the clearing agent

A

False

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5
Q

Most common dehydrating agent

A

Xylene/ xylol

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6
Q

True or false:

good clearing agent should dissolve out aniline dye

A

False. It should not dissolve aniline dye

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8
Q

Cedarwood is hard to remove from tissues in paraffin bath making wax impregnation process very slow. What could be done to avoid this?

A

Transfer the specimen from oil to benzene for half hour before finally placing the tissue in wax

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9
Q

True or false:

A good clearing agent should be miscible with and easily removed by melted paraffin wax and/ or mounting medium

A

True

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10
Q

Clearing time of xylene

A

30mins to 1hr

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11
Q

The following are true about xylene except?
A. It is the most rapid and also cheap
B. Suitable for nervous tissue and lymph nodes
C. It does not dissolve celloidin and can be used for celloidin sections
D. It becomes milky when an incompletely dehydrated tissue is immersed in it

A

B. It is not Suitable for nervous tissue and lymph nodes because it causes considerable hardening and shrinkage of tissues

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12
Q

Substitute for xylene

A

Toluene

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13
Q

Clearing time of toluene

A

1-2hrs

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14
Q

Excessive exposure to benzene may be extremely toxic and cause what?

A

Aplastic anemia

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16
Q

Clearing agent that is used for thick blocks (1 in thickness)

A

Chloroform

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17
Q

Clearing time of chloroform

A

6-24hrs

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18
Q

A clearing agent that is rapid acting and is recommended for urgent biopsies

A

Benzene

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19
Q

The process whereby dehydrating agent is removed from the tissue

A

Clearing/ de-alcoholization

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20
Q

Tissue tends to float in chloroform. What should be done to avoid this?

A

Wrap the tissue with absorbent cotton gauze

21
Q

Recommended for clearing embryos, insects, and very delicate specimens

A

Aniline oil

22
Q

Especially recommended for central nervous tissue

A

Cedarwood oil

23
Q

True or false:

Tissues placed in chloroform do not become transparent

A

True

26
Q

True or false:

Chloroform is recommended for tough tissues, nervous tissues, lymph nodes and embryos

A

True

31
Q

True or false:

Clearing fluids with low boiling point are generally more readily replace by melted paraffin wax

A

True

33
Q

True or false:

If tissue is left for 24hrs in toluene, the tissue becomes excessively hard and brittle

A

False. It does not

44
Q

True or false: clearing agent must be miscible with paraffin wax in order to facilitate penetration or this embedding medium

A

True