Histology, sometimes called microanatomy, is the study of cells and tissues to determine their functions in the human body. Since cells cannot be observed by the naked eye, histologists often use light and electron microscopes. To view and analyze cells under a microscope, slides are prepared and stained to aid the observer in detecting these structures. These slides can also be stored for a prolonged period of time for further analysis.
Obtain a slide and a sample of the tissue to be prepared on the slide.
Immerse the sample in a beaker of a chemical fixative, such as formaldehyde, to preserve the cell structure for 24 hours. This will keep the cell in stasis, or a state of stability, by preventing metabolism and degradation. This also is useful in hardening the tissue.
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Take the sample out of the chemical fixative. Remove excess water from the sample by using alcohol. This increases the visibility of the cell structures in the sample. However, since alcohol doesn't mix with the wax or plastic in which the sample will next be embedded, use a cleaning agent on the sample to remove the alcohol. Toluene and xylene are two such cleaning agents.
Embed the tissue sample in wax or plastic. This makes the tissue hard enough to cut into thin sections. The sample is then sliced into thin sections of tissue, usually 5 to 7 micrometers in thickness.
Stain the slide for increased visibility. Different stains can be used depending on the interactions the dye will have with the tissue sample. For instance, hematoxylin and eosin dye are used in combination. Hematoxylin is a basic blue dye that binds to positively charged structures, while eosin is an acidic pink dye that binds to negatively charged structures. You should choose the dye according to the tissue sample and the types of cell structures you want to enhance for viewing under the microscope.
Toluene, xylene and formaldehyde are toxic.