histo technique (lab) Flashcards
preparation of tissue slices or “slices” that can be examined visually through transmitted light
Histotechnique
ideally, the tissue on the slide should have the same ________ as it had in the _____ .
structural features, body
accessioning: what are the requirement of the specimen to be accepted.
-suitable container
-covered or closed
-large enough to hold the specimen without distortion
-adequate amount of fixative (submerged fully)
-properly labeled
-correct requisition form
ratio of specimen to fixaive
1:20
type of examination that cuts a small section of a specimen and placing in a plastic cassettes.
Gross examination
who can perform the gross examination
Pathologist
tissue processing
-fixation
-dehydration
-clearing
-infiltration
-embedding
-sectioning
-deparaffinization
-staining
-mounting
tissue specimen is placed in solutions of chemicals that cross-link proteins and inactivate degradative cazymes
fixation
duration process of fixation
12-72 hours
type of fixatives
aldehydes:
-buffered isotonic 37% formaldehyde
-glutaraldehyde -electron microscopy
ALCOHOLS
*used for cytologic smears
-methanol (blood smear)
-ethanol (pap smear)
an optional tissue process if the specimen contains/has calcium
Decalcification
duration of the decalcification
days to weeks
decalcifying agents
Strong mineral acids
-nitric acids (most common)
-hydrochloric acid
weak organic acids
-formic acid
-trichloroacetic acid
Chelating agents
-EDTA
type of tissue process where water is extracted gradually by transfers through a series of increasing Ethanol solutions.
Dehydration
what is the concentration of the ethanol that the specimen should be dipped at
70%
what is the order of the ethanol concentration
70%,90%,100%
type of process that give the tissue a translucent appearance
clearing
type of clearing agents
-xylene
-toluene
what is the most common clearing agent
xylene
type of tissue process that place the specimen in a melted paraffin in an oven
Infiltration/Impregnation
this step of Histotechnique evaporated the cleaning solvent
Infiltration/Impregnation
type of automated processing machine
-tissue transfer machine/ rotary type
-fluid transfer machine/ vacuum type
specimen is placed in a mold then filled with melted paraffin wax. what type of tissue processing?
Embedding
this process ensure proper orientation of the specimen
embedding
type of process that the block is placed in microtome for cutting
sectioning
what should be the thickness of the specimen to view in a light microscopy
3-10 um
what should be the thickness of the specimen to view in a electron microscopy
<1 um
type of tissue process that removes the paraffin from the slide
deparaffinization
type of tissue process that highlights the important features of the tissue as well as to enhance the tissue contrast.
staining
anionic (negative charge)
basophilic
cationic (positive charge)
acidophilic
what is the most common used for tissue stain
Hematoxylin & Eosin (H&E)
type of stain that highlights a tissue that contains glycogen & mucin
Periodic acid schiff (PAS) reaction
type of stain that highlights tissue that has lipids
Sudan Black
stain for silver and gold
metal impregnation
type of tissue process the protects the specimen with glass coverslip with clear adhesive.
mounting
Duration of fixatation if specimen is small
2-4hrs
