[2S] UNIT 6 Clearing Flashcards
is the process whereby alcohol or a dehydrating agent is removed from the tissue
Clearing
The tissue is replaced with a substance that will dissolve the
-Wax w/ which the tissue is to be impregnated (e.g. paraffin)
-Medium on which tissue is to be mounted (e.g.Canada Balsam)
Clearing
FUNCTIONS OF CLEARING AGENT
When used after ______ _______, it serves to mix with alcohol and remove it from the tissue
alcohol dehydration
FUNCTIONS OF CLEARING AGENT
When used after tissue section has been stained, it will make the microscopic tissue preparation _______
transparent
FUNCTIONS OF CLEARING AGENT
When tissue is to be cleared directly from water, it will merely improve _______ ______ of the tissue. (Glycerin and Gym syrup), no
dealcoholization involved.
refractive index
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It should be immiscible with alcohol/dehydrating agent
F; miscible
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It should be miscible with and easily removed by paraffin wax
T
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It should make tissues transparent and artifacts-free
T
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It makes the tissue translucent for better staining
F; transparent
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It should not produce excessive shrinkage, hardening
T
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It improves features under the microscope
T
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It should not evaporate quickly in a water bath
T
CHARACTERISTICS OF A GOOD CLEARING AGENT
T/F: It should dissolve out aniline dyes
F; NOT
3 Factors Affecting Clearing
Boiling Point
Viscosity
Prolonged exposure to clearing agent
Causes tissue to become brittle
Prolonged exposure to clearing agent
Affects the speed of penetration of the clearing agent
Viscosity
Those with low boiling point are more readily replaced by melted paraffin
Boiling Point
T/F: The choice of a clearing agent depends upon the processor system to be used
T
T/F: The choice of a clearing agent depends upon the intended processing conditions such as temperature, vacuum and pressure
T
T/F: The choice of a clearing agent depends upon the safety factors
T
T/F: The choice of a clearing agent depends upon the leisurely removal of the dehydrating agent
F; speedy removal
T/F: The choice of a clearing agent depends upon the cost & convenience
T
T/F: The choice of a clearing agent depends upon the ease of removal by molten paraffin wax
T
T/F: The choice of a clearing agent depends upon the minimal tissue damage
T
Commonly used clearing agents
- Xylene
- Toluene
- Benzene
- Chloroform
- Cedarwood Oil
- Aniline Oil Clove Oil
- Carbon tetrachloride
Clearing time of xylene
1/2-1 hr
- Colorless
- Most commonly used
Xylene (Xylol)
Generally suitable for routine histologic processing schedules of less than 24hours and when tissue block is less than 5mm in thickness
Xylene (Xylol)
Used for clearing, both for embedding and mounting procedures
Xylene (Xylol)
