Preparation of Temporary Slides.pptx

PREPARATIONOF TEMPORARY SLIDES

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2. Preparation of temporary slides

3. Temporary Slides made for the purpose of short time observations. After the observation session, they are discarded. In most cases the slides use a liquid mounting medium, such as water. ‹#›

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5. Preparation of Temporary Slides This may involve sectioning, staining and mounting. ‹#›

6. 1. Sectioning is an important step for the preparation of slides as it ensures a proper observation of the sample by microscopy. Sections are cut on a precision instrument called a “microtome” using extremely fine steel blades. ‹#›

7. 2 . Staining increases contrasts in order to recognize and differentiate the different components of the biological material. Apart from a few natural pigments such as melanin, the cells and other elements making up most specimens are colorless. In order to reveal structural detail using brightfield microscopy, some form of staining is required. ‹#›

8. STAINS Stains are used to help identify different types of cells using light microscopes. They give the image more contrast and allow cells to be classified according to their shape (morphology) Stains can also help differentiate between living or dead cells. ‹#›

9. Stains tend to be grouped as neutral, acidic or basic, depending upon their chemical makeup and will attract or repel different organisms accordingly. ‹#›

10. ‹#› Stain Types

11. Iodine is one of the more commonly available stains and is used to identify starch in a variety of samples. It will stain carbohydrates in plants and animal specimens brown or blue-black. Glycogen will show as red. ‹#›

12. Methylene Blue is an alkaline stain useful in identifying acidic cell nuclei and DNA in animal, bacteria or blood samples. It’s also useful in aquariums to prevent the spread of fungal infections in fish. ‹#›

13. Eosin Y is an acidic stain which stains pink for alkaline cells (cytoplasm, for example). It colors red for blood cells, cytoplasm and cell membranes. Eosin's most important medical uses are in blood and bone-marrow testing, including the PAP smear. ‹#›

14. Gram's Stain is one of the most frequently used processes in identifying bacteria – used daily in hospitals. It is a primary test that quickly and cost effectively divides bacteria into one of two types: Gram positive or Gram negative. ‹#›

15. 3 . Mounting Sections are mounted between slides and coverslips using a product to ensure adhesion. The slides are then ready for storage or observation. For fluorescence microscopy observations, a mounting medium is used in order to temporarily decrease the fluorescence loss. ‹#›

16. common ways to mount a microscope slide ‹#›

17. Dry Mount In a dry mount, the specimen is placed directly on the slide. A cover slip may be used to keep the specimen in place and to help protect the objective lens. Dry mounts are suitable for specimens such as samples of pollen, hair, feathers or plant materials. ‹#›

18. Wet Mount In a wet mount, a drop of water is used to suspend the specimen between the slide and cover slip. Wet mounts are suitable for studying water-bound organisms such as paramecium or bodily fluids such as saliva, blood and urine. ‹#›

19. Section Mount In a section mount, an extremely thin cross-section of a specimen is used. Using a microtome, cut a thin slice of your selected specimen such as an onion, and carefully set it on your slide. Section mounts are suitable for useful for a wide variety of samples such as fruit, vegetables and other solids that can be cut into small slices. ‹#›

20. Smear A smear is made by carefully smearing a thin layer of the specimen across a slide and then applying a cover slip. Typically, a smear should be allowed to air dry before applying a stain. ‹#›

21. Steps in preparing temporary slides Place a drop of fluid in the center of the slide. Position sample on liquid, using tweezers. At an angle, place one side of the cover slip against the slide making contact with outer edge of the liquid drop. Lower the cover slowly, avoiding air bubbles. Remove excess water with the paper towel. ‹#›

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23. Advantages and Disadvantages ‹#›

24. advantages Quick preparation Few artifacts Living and moving Natural colors ‹#›

25. Disadvantages Movement Evaporation Focus Storage ‹#›

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