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28 Cards in this Set
- Front
- Back
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what is histology?
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study of microscopic structures of the body
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what are the two major types of microscopy?
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light microscopy
electron microscopy |
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what are the three tissue preparation methods?
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embedding or freezing
cutting, sectioning staining |
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what are the wavelengths of light utilized by light microscopy?
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visual (397nm - 723nm)
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what are the three glass lenses of a light microscope?
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condenser lens - focus light on specimen
objective lens - magnifies apparent size of specimen ocular lens - further increases size of image |
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what is a compound microscope?
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a microscope with multiple objective lenses, of different magnification, mounted on a turret
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what is a bright-field microscope?
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the type of condenser on the microscope illuminates the entire field
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what is required of specimens for compound bright-field microscopy?
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must be translucent and stained to be visible
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what is a dark-field microscope?
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microscope with a special condenser which creates a high-contrast image of the specimen
permits detection of very small crystals, small organisms, and cell appendages |
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what are the clinical uses of dark-field microscopy?
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detect crystals in urine
detect syphilis organism (spirochete treponoma pallidum) |
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for what are polarizing microscopes used?
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allow selective visualization of birefringent structures (as bright spots on a dark background), which are repetitive or crystalline
(muscle fibers, crystalloid inclusions in cells) |
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for what are fluorescence microscopes used?
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permits visualization of fluorescent compounds
(visualize antibody markers or cDNA probes) |
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for what are phase contrast microscopes used?
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viewing unstained material, such as living cell cultures by converting slight differences in refractive index, present in different parts of a cell or tissue, into visible differences in light intensity, making a histological stain unnecessary
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what are differential interference microscopes?
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modified phase-contrast microscopes that create a 3D image that highlights either surface of a cell or internal components
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what wavelength of light is used for electron microscopy?
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0.005nm
(illuminated by a beam of electrons) |
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what act as the lenses for electron microscopy?
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electromagnets that focus the electrons onto the sample (glass lenses would deflect the electrons)
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with what are samples for electron microscopy embedded, sectioned, mounted, and stained?
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embedded in plastic
sectioned with glass or diamond knives mounted with copper grid stained with heavy metals |
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what is revealed by transmission electron microscopy?
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internal structure of cells and tissues
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what is revealed by scanning electron microscopy?
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visualization of the surface of cells and tissues
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what is used to section tissue?
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paraffin-embedded tissue blocks are sectioned on a microtome
frozen tissues are sectioned on a freezing microtome (cryostat) electron microscopy sections via ultramicrotome |
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what type of stain is H&E stain?
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hematoxylin& eosin stain is an acid/base stain
eosin - pink - acidophilic cells hematoxylin - blue - basophilic cells |
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what are the lipid soluble dyes?
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dyes that are more soluble in lipid than water which are used to demonstrate normal lipid distributions and disease-related lipid accumulations
ex. Sudan black, osmium |
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what are carbohydrate stains?
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stains for complex carbohydrates, like glycogen
ex. periodic acid-Schiff stain (PAS) |
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what is enzyme histochemistry?
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technique used to locate enzyme activity in particular cells, tissues and organelles
tissue incubated in solution with substrate for enzyme and chromogen which precipitates at site of enzymatic activity |
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what is immunocytochemistry?
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use of antibodies to localize a specific protein or carbohydrate group within a tissue
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what are nucleic acid stains?
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fluorescent compounds with affinity for nucleic acids - acridine orange, ethidium bromide, DAPI
basic dyes - toluidine blue Feulgen's reaction (HCl + Schiff reagent) - determine concentration of DNA in cell |
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for what are silver stains used?
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cytoskeletal elements and slender processes of NERVOUS SYSTEM
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what is autoradiography?
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the synthesis and movement of macromolecules in cells (“time-lapse histology”) is studied by injecting radioactive isotopes into an animal and then harvesting the tissue of interest at multiple timepoints
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