technique viva Flashcards
(27 cards)
how specimen reaches histopathology lab?
saline
formalin
transport media
onsite evaluation done by?
naked eye, hand lens and frozen
fresh biopsy
nerve - coz metachromatic granules disappear
muscle biopsy does not support paraffin sections
enzyme histochemistry can be done only
what are the reason for bad H&E section?
less than minimum 6 hours fixation
commercially available formalin
40% formaldehyde
Mechanism action
Methylene hydrate
washing formalin
50% removed by washing a week
formalin penetration
0.5mm/hour
Glutaraldehyde problem with PAS
false positive
ethanol
glycogen precipitated by this
picric acid explosive
when dry
can special stains be automated?
yes
What are the factor affecting tissue processing?
Heat
Agitation
viscosity
vacuum
types of microtome
rotary
base sledge
profile of blade
small profile
large profile
angle of tilt?
10 to 20 degree
how do you coat slides for histopathology?
egg albumin - mayers
components of dyes?
chromophore - absorb light
auxochrome - side chain ionisable, reactive
sulphonic carboxylic phenolic
types of auxochoromes
acidic
basic
neutral
what is progressive staining?
dye allowed to act slowly
What is regressive staining?
overstrain section and do controlled destain
Color of hematoxylin
colourless
active component of hematoxylin
hematin