WEEK 2 (Microscopy) Flashcards
Name the three lenses that compose the optical component of the ‘Bright Field microscope’
Condenser
Objective
Eyepiece
Define ‘Resolving power’
The smallest distance between two structures at which they can be seen as separate objects
What are the properties of ‘Fluorescent microscopy’?
- Microscope has a source of UV or other light and filters that select rays of different wavelengths emitted by the substances to be visualised
- Fluorescent compounds with affinity for specific cell macromolecules can be used as fluorescent stains
What are some examples of fluorescent stains?
- Acridine orange
- DAPI (4’, 6-diamino-2-phenylindole)
- Hoechst
Which type of light microscopy produces visible images from transparent objects and living, cultured cells?
Phase-Contrast microscopy
What is the principle that Phase-Contrast microscopy is based on?
It is based on the principle that light changes its speed when passing through cellular and extracellular structures with different refractive indices
What is the name of the type of Phase-contrast microscopy that produces a 3D image of living cells?
Differential interference contrast microscopy
How does Confocal microscopy achieve high resolution and high focus?
- a small point of high intensity light (often from a laser)
- a plate with a pinhole aperture in front of the image detector
What is distinguishable about Polarising microscopy?
It is used in the recognition of stained or unstained structures made of highly organised subunits. It relies on the birefringence of crystalline substances and highly oriented molecules.
Define ‘Birefringence’
The ability to rotate the direction of vibration of polarised light; it is the feature of crystalline substances or substances containing highly oriented molecules
What are the different types of Light microscopy?
Bright Field Microscopy
Fluorescent Microscopy
Phase-Contrast Microscopy
Confocal Microscopy
Polarising Microscopy
What are the different planes of the body?
Coronal plane
Horizontal plane
Sagittal plane
Transverse plane
Axial plane
What is the role of the condenser in the Bright field microscope?
It condenses the light beam
What are the two types of Electron Microscopes?
Transmission Electron Microscopes (TEMs)
Scanning Electron Microscopes (SEMs)
What makes the electron microscope better than the light microscope?
The electrical current in the electron microscope has better penetration than the light rays in the light microscope therefore can identify smaller structures
