Light microscopy Flashcards
What is resolution determined by?
The wavelength of the radiation source used for illumination.
What is a light microscope?
An instrument that uses visible light and magnifying lenses to examine small objects not visible under the naked eye.
How can magnification be increased?
Lenses can be added one behind another - compounded.
How does the classic compound microscope work?
The object is magnified by a first objective lens to produce a real image, which is then magnified by a second lens to produce a virtual image.
What is resolution?
The clarity of an image.
Who improved the production of lenses?
Antony van Leeuwenhoek.
Who was the first to name a cell?
Robert Hooke.
What does a condenser do in a microscope?
It focuses light rays on the specimen.
What are the different types of light microscopy?
Bright field, phase contrast, DIC, fluorescence and confocal.
Why does contrast need to be increased in samples?
In order to see details.
How does bright field compare to phase contrast and DIC?
They are much poorer images with low contrast.
How is contrast created in phase contrast?
Minute variations in phase are translated to changes in amplitude, which appears as contrast.
How does DIC work?
A prism splits a beam of polarised light into two. This creates contrast as if one of the beams is diffracted by the specimen, when they are recombined by another prism they will interfere and create contrast.
How can cellular components or cell types be detected with the conventional bright field microscopy?
DYes, chromogenic enzyme substrates or dyes-included or excluded.
What is fluorescence?
The property of absorbing light of a particular wavelength and then emitting light of a different colour and wavelength.
