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• What is microtomy? Microtomy is the process of trimming and cutting processed tissue into thin slices for microscopic studies.
• What is the remedy for brittle or hard tissue during tissue processing? If tissue becomes brittle or hard due to prolonged fixation, soak the tissue in a bowl containing water with phenol.
• What should be done if the clearing agent turns milky during tissue processing? If the clearing agent turns milky due to incomplete dehydration, repeat dehydration with absolute alcohol and then clear again.
• What should be done if wax appears crystalline during trimming? If wax appears crystalline due to contaminated wax, re-embed the tissue in freshly filtered wax.
• How to remedy frozen tissue chipping into fragments during cutting? If tissue chips into fragments when cut due to being too hard from freezing, warm the tissue with the fingers before cutting.
• What is a Compound Embedding Unit? A series of interlocking plates resting on a flat metal/rubber base, forming several compartments. Advantage: Embedding more specimens at a time, reducing time needed for blocking.
• What are the four types of embedding media? 1. Paraffin wax
• 2. Celloidin
• 3. Gelatin
• 4. Plastic
• What are the three types of Disposable Embedding Molds mentioned? 1. PEEL AWAY
• 2. Paper Boats
• 3. Plastic Ice trays
• What is an ultrathin microtome used for? An ultrathin microtome is used for cutting tissues in preparation for electron microscopy, producing sections as thin as 0.5 microns.
• What are the requirements for specimens in an ultrathin microtome? Specimens must be small, fixed in osmium tetroxide, and embedded in plastic before being cut.
• What is the typical thickness of sections cut for routine histologic procedures? Sections are usually cut between 4-6 microns in thickness for routine histologic procedures.
• At what angle is the knife usually tilted on a microtome? The knife is usually tilted at 0-15 degree angulation on a microtome for cutting sections.
• What is the purpose of an ultrathin microtome? Cutting tissues in preparation for electron microscopy.
• What specific size are tissues cut to using an ultrathin microtome? 0.5 micra thin.
• What type of knife is used in an ultrathin microtome? Fragments of broken plate glass.
• What are the essential parts of a microtome? Block holder, knife carrier and knife, pawl, ratchet feed wheel, adjustment screws.
• What is a sliding microtome used for? Celloidin embedded sections.
• What is staining? Staining is the process of applying dyes on tissue sections to study architectural patterns and cell characteristics.
• What is tissue staining? Tissue staining is the process of demonstrating tissue constituents in sections through direct interaction with dyes or staining solutions.
• What is metachromasia? Metachromasia is when dyes stain tissues with a different color from the dye itself.
• Give examples of dyes that exhibit metachromasia. Examples of dyes that exhibit metachromasia include Methyl violet, Cresyl blue, Safranin, and Bismarck Brown.
• How can tissue substances be localized microscopically? Tissue substances can be localized microscopically through chemical reactions during the staining process.
• How are various constituents of tissues studied? Various constituents of tissues are studied through chemical reactions that permit microscopic localization of a specific tissue substance.
• What is tissue staining a combination of? Tissue staining is a combination of immunologic and histochemical techniques that allow phenotypic markers to be detected.