Clearing

Question 1

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

Answer 1

Aniline oil

Question 3

True or false:

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

Answer 3

False

Question 5

Most common dehydrating agent

Answer 5

Xylene/ xylol

Question 6

True or false:

good clearing agent should dissolve out aniline dye

Answer 6

False. It should not dissolve aniline dye

Question 8

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

Answer 8

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

Question 9

True or false:

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

Answer 9

True

Question 10

Clearing time of xylene

Answer 10

30mins to 1hr

Question 11

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

Answer 11

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

Question 12

Substitute for xylene

Answer 12

Toluene

Question 13

Clearing time of toluene

Answer 13

1-2hrs

Question 14

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

Answer 14

Aplastic anemia

Question 16

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

Answer 16

Chloroform

Question 17

Clearing time of chloroform

Answer 17

6-24hrs

Question 18

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

Answer 18

Benzene

Question 19

The process whereby dehydrating agent is removed from the tissue

Answer 19

Clearing/ de-alcoholization

Question 20

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

Answer 20

Wrap the tissue with absorbent cotton gauze

Question 21

Recommended for clearing embryos, insects, and very delicate specimens

Answer 21

Aniline oil

Question 22

Especially recommended for central nervous tissue

Answer 22

Cedarwood oil

Question 23

True or false:

Tissues placed in chloroform do not become transparent

Answer 23

True

Question 26

True or false:

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

Answer 26

True

Question 31

True or false:

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

Answer 31

True

Question 33

True or false:

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

Answer 33

False. It does not

Question 44

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

Answer 44

True