Histology Methods Flashcards
Routine laboratory microscope used for studying tissue sections
Light (bright field) microscope
used to study cytology or internal structures of cells
Transmission electron microscope (TEM)
used to study the surface features of cells and tissues; obtain a 3-dimensional picture of the tissue
Scanning electron microscope (SEM)
permits one to determine whether biological materials have different refractive indices along different optical axes
Polarizing microscope
used to study living tissue; works on principal of different refractive indices of cellular and sub-cellular components
Phase microscope
a modification of the phase microscope used for the study of living tissue
Interference microscope
uses UV light as the light source; used to examine the presence of fluorescent material in tissue sections
Fluorescence microscope
uses a laser energy beam; used to optically section a cell and with the appropriate computer equipment can reconstruct a 3-D image of the cell
Confocal scanning microscope
What are the steps of tissue prep for light microscopy?
- Fixation
- Dehydration
- Clearing
- Infiltration and embedding
- Sectioning
- Staining
How can frozen tissue sections be used?
- surgical biopsy
- pathologically ID’ing localization of enzymes
What are some types of artifacts the may be introduced into samples?
- Post-mortem degeneration
- Shrinkage
- Precipitates
- Wrinkles and folds
- Nick in microtome knife
- Mishandling of the tissue
What is hematoxylin?
- Basic dye (has chromophore in cation); positive charge
- likes basophilic substances (those with net negative charge)
What is eosin?
- acid dye (chromophore in anion); negative charge
- likes acidophilic substances (those with net positive charge)
What is the Feulgen stain for?
DNA
What is the mechanism of a Periodic Acid Schiff reaction (PAS)?
- Periodic acid opens up sugars to form aldehyde groups.
- Aldehyde groups then react with Schiff’s reagent to produce a colored red product
*can be used to ID carbs and DNA
