Histology Flashcards
Where do we find artifact pigments?
On top of the tissue
-only formalin pigments are found within the cell cytoplasm
what is the most common cause of artifact pigments?
fixation
What are formalin pigments resistant to?
strong acids
What are some endogenous pigments?
hemoglobin, hemosiderin, porphyrins, bile pigments, melanin, lipofuchsin, ceroid
what are some exogenous pigments?
carbon, asbestos fibers, tattoo pigments, metals (ex: iron, Wilson’s disease),
what effect does formalin pigments have on silver?
Reduces it
What are some artifact pigments?
- chrome from fixative containing K dichromate (not washed out in running water prior to dehydration)
-formaldehyde pigment caused by fixating in acidic formaldehyde(pH less than 5.6) instead of buffered formaldehyde
-mercury pigment (cannot be prevented)
What is the cryostat temperature?
-18 to -20
what size does the microtome cut?
4-6 um
what is the paraffin bath temperature?
45C
What chemical fixative is used to prepare tissue for electron microscopy?
gluteraldehyde
What is the melting point of paraffin?
55-58C
Which of the following stains is used to demonstrate mycobacterium leprae?
a. Gram
b. Fite
c. Brown and Brenn
d. Grocott methenamine silver
B
What type of tissue cuts easier using a cryostat?
A. Tissue w/ high water content
B. Tissue w/ low carb content
C. Tissue w/ high fat content
D. Tissue w/ low water content
D
What fixing agent counteracts shrinkage:
Acetic acid
