Microscopy and its significance

its about the microscopes types and there significance in the world for diagnostic purposes .advantages and disadvantages of the types of different microscopes

1. Microscopy and its significance Name : Rohama Roll no : 24

2. Phase contrast microscopy It was developed by the Dutch physicist Frits Zernike in the 1930 s. It is used for studying unstained cells. It uses light microscope fitted with phase contrast objective and phase contrast condenser . It distinguish unstained parts of cell which differ in their refractive indices and thickness. It is widely used in theoretical biological studies.

3. Principle Based on the fact light passing through one material and into another material of different refractive indices and thickness will undergo a change in phase these differences are regulated into variations in brightness They are detectable by eye

4. Advantage Possible to reveal differences in cells. Reveal differences in their structures. Not possible by other microscopes.

5. Fluorescence microscopy Application of fluorescence phenomena is the basis of fluorescence microscopy. What is florescence? chemicals absorbing emitting light of light of shorter wavelength longer wavelength and high energy and less energy Microorganism is stained with florescent dye Illuminated with blue light and green light is emitted

6. Fluorescent antibody technique Fluorescent dyes + Antibodies labeled antibodies + suspension of bacterial cells examined with fluorescence microscope By this it is possible to identify the single bacterial cell. Application of this test in diagnostic procedures.

7. Transmission electron microscope The transmission electron microscope (TEM) uses a high voltage electron beam to illuminate the specimen and create an image. It provides high resolution due to shorter wavelength. It is possible to resolve objects as small as 10 angstrom Its resolving power is 100 times more than of light microscope. Its magnification is x 400,000.

8. working Specimen to be examined is prepared in thin dry films. The electron beam is produced by an electron gun , commonly fitted with a tungsten filament cathode as the electron source. Slide is introduced between magnetic condenser and magnetic objective Magnified image Airtight window by a camera On fluorescent screen on photographic plate

9. Scanning electron microscope The SEM produces images by probing the specimen with a focused electron beam that is scanned across a rectangular area of the specimen the electron beam interacts with the specimen energy loss heat, emission of low-energy secondary electrons and high-energy back scattered electrons or x-ray emission all of them carries information about the properties (specimen)

10. Stereo microscope It is variant designed for low magnification observation of a sample. Using light reflected from the surface of an object rather than transmitted through it. The instrument uses two separate optical paths with two objectives and eyepieces to provide slightly different viewing angles to the left and right eyes . This arrangement produces a three-dimensional visualization of the sample being examined.

11. Significance Microscopes help the scientists to study the microorganisms , the cells crystalline structures and the molecular structures . Microscopes magnify the blood samples , so , The doctors can see the malaria parasites attacking the red blood cells . Scanning electron microscopes have the magnifications up to several million times to view the molecules , the viruses and the nano-particles. Microscopes enlarge the images of silicon chips to help the engineers create more efficient electronic devices . All branches of biology uses Microscopes especially in Molecular Biology and Histology ( study of cells ) .

12. Microscopes are used to diagnosis the illness in the hospitals and the clinics all over the world By using Microscopes scientists were able to discover the existence of the microorganisms , study the structure of cells , and see the smallest parts of plants , animals , and fungi . Microscopic examination confirms the laboratory tests that may be positive for the disease.