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19 Cards in this Set
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Explain the following terms as they relate to histology andgive one example of each: electrostatic binding |
Stains used in light microscopy bind to molecules in cells and tissues of opposite charge. Thus, positively charged dyes (basic dyes) bind to negatively charged molecules and negatively charged dyes (acidic dyes) bind to positively charged molecules. Ex: eosin is an acid dye with a negative charge, which means it's basophilic, so it binds to bases, such as proteins, which are acidophilic. |
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Explain the following terms as they relate to histology andgive one example of each: acidophilia |
"Acid loving." Most common acidophilic molecules in cells are proteins. Collagen fibers exhibit acidophilia, they are rich in proteins. |
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Explain the following terms as they relate to histology andgive one example of each: basophilia |
"Base loving," binds to a basic dye. Most common basophilic substances in cells and tissues are nucleic acids. Regions of the cell rich in NA such as the nucleus or nucleouls, exhibit basophilia. |
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Explain the following terms as they relate to histology andgive one example of each: mordants |
Charged substance which, when mixed with an electrically neutral stain, acts as a binder. Eg: Hematoxlyin, which will not stain tissues and must be mixed with metal atoms (+ charged) to enable the binding with negatively charged molecules. Color which hemoxylin stains depends on the mordant (eg: iron or K-alum) |
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Explain the following terms as they relate to histology andgive one example of each: magnification |
the size of the image of an object relative to the original object an object with a diameter of 1 micrometer that is enlarged to an image 1 mm (1000 micrometers) in diameter is said to be magnified 1000 times (1000 x) |
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Explain the following terms as they relate to histology andgive one example of each: resolution |
a measure the smallest objects that can be distinguished as separate objects ex: when we look into the night sky, our eyes lack the ability to distinguish a single star from a galaxy - they both appear to us as a single point of light. This is because our eyes cannot resolve the millions of stars that make up the galaxy as single objects |
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Explain the following terms as they relate to histology and give one example of each: |
the degree to which the image of an object stands out from its background ex? |
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Explain the following terms as they relate to histology and give one example of each: numerical aperture |
the measurement of the light gathering capacity of a lens |
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Explain the following terms as they relate to histology and give one example of each: contrast |
The ability of an object to be distinguished visually from its background staining biological structures to add color to various cellular and tissue components (amplitude contrast) |
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Explain the following terms as they relate to histology and give one example of each: refractive index |
? degree to which light is bent when traveling through a medium
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what are the steps required to prepare tissues for microscopic examination? define them |
1. Fixation (formaldehyde) - treating the sample to preserve it for study 2.Dehydration - removing water to permit the sample to be embedded in a non-aqueous medium 3. Embedding (paraffin) - impregnating and surrounding the sample with a medium that is sufficiently hard to allow it to be cut into thin slices 4.Sectioning - slicing the sample into slices that are thin enough for the illuminating radiation to pass through it 5. Staining - differentially coloring different parts of the tissue to give them contrast |
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Explain the following terms as they relate to histology and give one example of each: covalent binding |
Osmium tetroxide (OsO4) is sometimes used as a stain in light microscopy because it binds covalently to lipids, causing them to appear black in the light microscope |
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Explain the following terms as they relate to histology and give one example of each: nuclear stain/counterstain |
nuclear stain stains the DNA of the nucleus, and a counterstain stains components of the cytoplasm and/or EC matrix |
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Explain the following terms as they relate to histology and give one example of each: polychrome stains |
mixture of stains which stains different components of tissues different colors ex: Wright's blood stain or Mallory's Triple Stain |
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Explain the following terms as they relate to histology and give one example of each: orthrochromasia |
property by which stains color tissue components the color of the dye used |
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Explain the following terms as they relate to histology and give one example of each: metachromasia |
property by which some stains produce more than one color in a tissue ex: azure dyes, which are blue, stain DNA blue but stain certain substances purple or red (ie cell granules) |
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Explain the following terms as they relate to histology and give one example of each: histochemical staining |
A method used to detect or reveal the location of specific substances by treating tissues in various ways. To study individual cells-->cytochemistry ex: PAS reaction-allows carbs to be stained magenta Fuelgen reaction: differentiates DNA from RNA |
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Explain the following terms as they relate to histology and give one example of each: enzyme histochemistry |
method used to detect presence of specific enzymes by using the enzyme to generate a colored reaction product |
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Explain the following terms as they relate to histology and give one example of each: immunohistochemistry |
method which uses labeled antibodies to detect the presence of specific molecules in tissues and cell |
