Answer
In order for a tissue to be studied histologically by light microscopy (LM). It mis be fixed ( formalin/ Bouins fluid) dehydrated ( alcohol) infiltrated/ embedded in paraffin wax. After embedding the tissue is mounted on a block and sectioned on a microtome. Very thin sections of the tissue 7-10 um are mounted on glass slides. The paraffin is washed out in some substance such xylene and the sections are rehydrated and stained in some stain such as hemotoxylin( stains nuclei) and eosin ( stains cytoplasm). The stained sections are differentiated , dehydrated and examined. To examine the sections, a drop of mounting media ( Canada Balsam) is place over the sections and a glass cover slip is lowered on top of the drop of Canada Balsam. The preparation is then placed on the stage of a light microscope and examined at low, medium and/or high magnification. There are numerous variations of this procedure. With this H & E staining technique, the nuclei of cells appear purple, and the cytoplasm is stained pink. For easy distinction of structures, adequate differentiation is critical.
Work Step by Step
Fluorescent, microscopy, phase contrast, and darkfield microscopy are other ways of examining tissue by light microscopy. Examining smears of tissues, like blood, is an important light microscopic method in histology.
