Introduction to Microscopy and Histology Flashcards
Who coined the word “cell” ?
Robert Hooke (50x mag)
Used microscope for life in water drop (protist), bacterium, spermatozoa, and circulation in blood
Leeuwenhoek (270X)
What is a light microscopy?
pass light through a specimen and this type of microscope is able to use both magnification and resolution to see the object under light
what is resolution?
allows you to see two close but distinct points
What are the steps for tissue imaging?
- fixation
- dehydration
- embedding
- sectioning
- rehydrate
- staining
When would you use the cyroalternative?
when you need to see the tissue immediately or need it for immunoflourance techniques EX: blood, bone marrow, epithelial cells
What are the steps for cyro- alternative staining?
- no dehydration
- embedding with gelatin or OCT
- deep freeze (isopentane or liquid nitrogen)
- sectioning with cryostat
- remove gelatin/ OCT
- staining
What is the purpose of rapid freezing?
prevents ice crystals, preserve cell strict, prevents damage
what are cytosections good fro?
detecting antigens
Frozen section are good for what?
immunochemistry, and enzymatic detection
What are cell smears?
things like bone marrow, blood, or epithelial cells are not sectioned, fixed in alcohol and stained right away
hematoxylin
basic dye that stains acidic components blue EX; nuclei , ribosome, RNA
eosin
acidic dye that stains basic components red-pink EX: proteins, collagen
Which dye would you use to look at mitotically active cells?
hematoxylin
Periodic acid-Schiff (PAS) staining?
pink, magenta used to stain carbohydrates
orcein
dark brown purple color, stain electric fibers
osmium tetroxide
stains lipids and myelin a dark brown color
Oil Red O
stains lipids red-orange in unfixed frozen sections
toluidine blue
high affinity for acidic busses. staines nucleic acid blue and polysaccharides purple. great for chromosome staining
metal impregnation
silver is commonly used, to demonstrate reticular fibers
Nissl Stain
selective staining developed by Nissl using an aniline stain to label extra-nuclear RNA granules- good for visualizing Rough ER
what is vital staining?
uptake of dyes by cells
trypan blue
identifies dead cells
engulfed by macrophage and can be used to delineate kipper cells of the liver
wright/glemsa stain
attach to DNA
used to stain blood, bone barrow, parasites
neutral red
in lysosome of liver cells.
red when protonated and colorless when unprotonated/permeable
janus green
changes color with different amounts of oxygen
- green= oxidized, in mitochondria
- colorless before
IHC
detection of antigen with antibodies in the tissue
ICC
detection og antigen with antibodies in isolated or intact cells
Facts about transmission electron microscope (TEM)
- passes electron through specimen
- focused by magnetic lens
- image is on fluorescent screen
- magnification=10,000,000X
- resolves .2nm object
Facts of scanning electron microscope (SEM)
- elections passed round specimen
- 1nm resolution
- 150,000X magnification
- detailed image of surface
