Microscopy Flashcards
What is magnification?
How many times bigger the image is than the real item
What is resolution?
The shortest distance between two points on a specimen that can still be distinguished by the observer or camera system as separate entities.
What does light microscopy use to determine image resolution?
Wavelength of light
What magnifies the image in a light microscope?
Objective lens and eyepiece lens
What is the rough resolution of light microscopy?
200nm
What are the three steps needed to prepare a sample for looking at under a light microscope?
Fixation
Sectioning
Staining
What is fixation?
Tissue will decay and breakdown so it must be fixed to keep cells in same state.
The sample is treated with chemicals so it is cross bound and kept at a very low temperature - supported in a wax block
Why is sectioning necessary for light microscopy samples?
The tissue sample must be sectioned so that it is thin enough for light to pass through.
Why is staining used?
Increases the contrast so individual compartments are more visible.
What does H&E stand for?
Haematoxylin and Eosin (H&E).
Which is the basic dye in H&E, what does it bind to?
Haematoxylin (binds to acids)
Which is the acidic dye in H&E, what does it bind to?
Eosin (binds to basic structures)
What colours are H&E?
H = purple E = pink
Is fat stained with H&E?
No
What is fluorescence microscopy?
Microscopes that collect fluorescence emission light. The sample is tagged to specific molecules that emit visible light of different colours when illuminated.
