Light microscopyBright field microscopyDark field microscopyPhase-contrast microscopyFluorescence microscopyElectron microscopy
LIGHT MICROSCOPY Uses a beam of light to view specimen. The commonest type used in clinical laboratories isthe compound light microscope. — it consist of two lens system to magnify the image. — each lens has a different magnifying power. — a compound light microscope may have a singleeye piece (monocular) or two eye pieces (binocular).
BRIGHT- FIELD MICROSCOPY The field of view is brightly lit so thatorganism and other structures are visibleagainst it because of their different densities. Single stain or differential staining may beused depending on the properties of differentstructure and organism. Widely used in histology , pathology , botany
DARK-FIELD MICROSCOPY The field of view is dark and theorganism are illuminated. A special condenser is used which causelight to reflect from the specimen at anangle. Used to observe living ,unstainedpreparations.
PHASE -CONTRAST MICROSCOPY Phase –contrast microscopy is a contrast enhancing opticaltechnique that can be utilised to produce high contrast images of transparent specimens , such as living cells , microorganisms and many other structures. Special condensers and objectives are used to alter thephase relationship of the light passing through the object andthat passing around it. Used in cell culture (to monitor growth of cells). Relatively inexpensive and simple.
FLUORESCENCE MISCROSCOPY In fluorescence microscopy specimens are stained withfluorochromes / flurochrome complexes. Light of high energy or short wavelengths (from halogen lamps ormercury vapour lamps) is then used to excited molecules within thespecimen or dye molecule attached to it. These excited molecules emit light of different wavelengths often ofbrilliant colours -> shows a bright image of the object resulting fromthe fluorescent light emitted by the specimen.
ELECTRON MICROSCOPY Composition: the elements and compounds that theobject is composed of and the relative amounts ofthem, direct relationship between composition andmaterial properties Crystallographic information : how the atoms arearranged in the ;direct relation between the arrangementsand material properties
PARTS FUCTIONS1. Eyepiece - Contain a magnifying lens that focuses the image from the objective into your eye.2. Course Adjust - For focusing under low magnification.3. Fine Adjust - For focusing under high magnification or low.4. Low Power Objective - For large specimen or overview.5. High Power Objective - For detailed viewing or small specimens.6. Specimen on glass slide - What you want to look at.7. Stage - Supports specimen in correct location to lens.
8. Condenser - Focuses the light on specimen.9. Diaphgrams - Regulates amount of light and contrast.10. Light Source - Illuminates the specimen for viewing.
HOW USING THE MICROSCOPE?1. To carry microscope grasp the microscopes arm with or hand.Place your other hand under the base.2. Place the microscope on a table with the arm toward you.3. Turn the coarse adjustment knob to raise the body tube.
4 . 4.Revolve the nosepiece until the low-powerobjective lens clicks into place.5. Adjust the diaphragm.While looking through theeyepiece,also adjust the mirror until you see abright white circle of light.6. Place a slide on the stage.Center the specimenover the opening on the stage. Use the stage clips tohold the slide in place.7. Look at the stage from the side. Carefully turn thecoarse adjustment knob to lower the body tube untilthe low power objective almost touches the slide.
8. Looking through the eyepiece, VERY SLOWLY thecoarse adjustment knob until the specimen comesinto focus.9. To switch to the high power objective lens, look atthe microscope from the side. Carefully revolve thenosepiece until the high-power objective lens clicksinto place. Make sure the lens does not hit the slide.10. Looking through the eyepiece, turn the fineadjustment knob until the specimen comes into focus.
MICROSCOPES CARE & HANDLING Transporting: When you pick up the microscope andwalk with it, grab the arm with one hand and place yourother hand on the bottom of the base. DON’T SWING THE MICROSCOPE! Handling & cleaning: Never touch the lenses with yourfinger. Your body produces an oil that smudges the glass.This oil can even etch the glass if left on too long. Use onlyLENS PAPER to clean the glass. TOILET PAPER,KLEENEX,AND PAPER TOWELS HAVE FIBERSTHAT CAN SCRATCH LENSES
Storage: when you are finished with your ‘scope’assignment,rotate the nosepiece so that its on the lowpower objective,role the nosepiece so that it’s all the waydown to the stage, then replace the dust cover . DON’T FORGET TO USE PROPER TRANSPORTING TECHNIQUES!Clean up: clean all slides, materials, and work areawhen you’re done. Please , be careful with the slide andcover slips. They are made of glass and if broken, youwill get cut and you will bleed.