Practical medical biology Light microscopy ppt

Types of light microscopes
Conventional bright-field microscopy
Fluorescence,
Phase-contrast
Confocal

are all based on the interaction of light and tissue components and can be used to reveal and study tissue features.


Magnification:
The increase of an object s apparent size,
your microscope has 3 magnifications: Scanning, Low and High .Each objective will have written the magnification .In addition to this, the ocular lens (eyepiece) has a magnification.
The total magnification is the ocular x objective.
fluorescence microscope

Principle
The specimen is illuminated with light of a specific wavelength which is absorbed by the fluorophores, causing them to emit light of longer wavelengths
(i.e., of a different color than the absorbed light).
Fluorescence microscopy requires intense, near monochromatic, illumination which some widespread light sources
Examples:
mercury-vapor lamps
lasers
LEDs
phase contrast microscopy
Phase-contrast microscopy is based on the principle that light changes its speed when passing through cellular and extracellular structures with different refractive indices. These changes are used by the phase-contrast system to cause the
structures to appear lighter or darker in relation to each other.