2nd LLE Flashcards
Used for delicate specimens and frozen tissue sections because it prevents fragmentation of tough and friable tissues
Gelatin impregnation
Embedding mold recommended for busy routine laboratories
Plastic ice trays
Method of paraffin wax impregnation gives the fastest result
Vacuum processing
Melting point of wax commonly used for routine procedures
56 C
Process by which tissue is arranged in precise position in the mold before embedding
Orientation
A series of interlocking plates resting on a flat metal base
Compound embedding unit
Gives superior results for a light microscopic studies in hard tissues like undecalcified bones
Plastic embedding
Acrylic plastic is for?
Light microscopy
Polyesters plastic is for?
Electron microscopy
At what temperature should a paraffin oven be maintained when used for impregnation
2-5 centrigade above melting point
Melting point of highly purified paraffin and synthetic plastic polymers
56-57 C
Most rapid clearing agent suitable for urgent biopsies
Xylol
It causes the minimum shrinkage of tissues but dissolves aniline dyes and celloidin
Clove oil
Recommended for embryos and very delicate specimen
Cedarwood oil
Considered carcinogenic and may damage the bone marrow resulting in a plastic anemia
Benzene
Carbon tetrachloride has properties similar to?
Chloroform
Recommended for fibroid and decalcified tissues
Chloroform
Characteristics of chloroform makes it unsuitable as a clearing agent
It does not make the tissue transparent
What clearing agent should be used when double embedding techniques are required
Methyl benzoate and Methyl salicylate
If both xylene and benzene are not available, which clearing agent can be used as a substitute?
Toluene
Refractive index of a plastic slide
1.518
Dehydrating agent that is toxic and is formally employed for blood and tissue films and smear preparation
Methyl alcohol
An excellent dehydrating and clearing agent that is readily miscible in water, melted paraffin, alcohol and xylol but is expensive and extremely dangerous
Dioxane
Process of removing intracellular and extracellular water from the tissue following fixation and prior to impregnation
Dehydration
What is added to the dehydrating agent that will act as a softener for hard tissues such as tendon, nail, or dense fibrous tissue
4% phenol
What dehydrating agent is combustible at 110-120 F and toxic by inhalation, skin contact, and ingestion
Ethylene glycol ethers
How does dehydration start with the concentration of the dehydrating agent
Increasing concentration
Recommended dehydrating agent for routine purpose
Alcohol
Dehydrating agent dehydrated rapidly to the point where tissue may be transferred from water and NSS directly to the dehydrating agent and stored there for months without hardening/distorting
Cellosolve and Ethylene glycol monoethyl ether
Recommended for cutting extremely hard and rough tissue block
Sliding microtome
Type of microtome reduces tissue sections of 0.5 inches in thickness
Ultrathin microtome
How many double strokes are presently given to each side of the knife in a mechanical knife sharpener
30 strokes
Used for cutting or trimming and/or for semi-thin sectioning of tissue blocks for electron microscopy
Glass knives
Process of removing the burr form during honing
Stropping
What should be the clearance angle made to prevent uneven tissue sections
5-10 degree
Only used for badly nicked knives
Fine carborundum
What microtome can be mounted on a bench-top
Freezing microtome
How many double strokes are required in the stropping process
40-120
First and most critical step in histotechnology which involves preserving the fresh tissue examination
Fixation
The step that gives the tissue a translucent appearance
Clearing
According to United States of CDC, regular hand washing helps eliminate the spreading of germs (true or false)
True
Prolonged fixation makes tissue blocks brittle and hard (true or false)
True
The medium used in embedding is the same medium used to infiltrate the tissue samples (true or false)
True
Cutting away the excess wax from the sides, top, and bottom of the tissue block until perfectly leveled on all sides of parallel to each other almost to the edge of the tissue
Coarse trimming
