Histology Testbank: Histology Stains and Techniques 1a
Instructions: For each histology question, pick the one best answer. This histology test bank is also useful for the histology questions on the USMLE (USMLE step 1).
"H&E" stands for hematoxylin and eosin. Hematoxylin can be thought of as a basic dye. It binds to acidic structures, staining them blue to purple. For example, it will bind and stain nucleic acids. Therefore, the nucleus stains blue.
Sudan stains are used for staining of lipids and phospholipids. Examples of such stains are sudan black and sudan IV. Oil red O is another stain used for demonstrating fat.
Mucicarmine is used to see epithelial mucin. It stains it a deep red.
Wright's stain is used for blood smears and bone marrow. Red blood cells will stain pink.
Verhoeff Elastic stain stains elastic fibers blue/black. Collagen stains pink/red.
There are several steps in the preparation of a slide for microscopic examination. First, the tissue is "fixed" with formalin. This preserves it. After the tissue is fixed, it is dehydrated (dehydration will occur twice during slide preparation). The tissue sample is then embedded in paraffin. This forms a solid block, so that it can be placed in a microtome. It is then thinly sliced using a microtome. A thin slice of the specimen is then placed on a slide. The paraffin is removed by dissolving it with a chemical. The tissue is then rehydrated. In order to view the tissue, it is stained. After it is stained, it is again dehydrated. A coverslip is the mounted on top of it. The specimen is then ready for viewing.
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