Glossary Flashcards
absorption
tissue is penetrated by, or absorbs, a dye solution and becomes colored without any other chemical change or chemical reaction occurring. An example is the absorption of oil red O or Sudan black B by fat.
achromatic
without color or not easily stained. In microscopy, achromatic lenses are corrected for 2 colors, red and blue. This helps produce images free of chromatic aberrations.
acid mucosubstances
a term used to include both the acid mucopolysaccharides (connective tissue mucins) and the acidic glycoproteins (epithelial mucins). Most acid mucopolysaccharides contain sialic acid. Acid mucopolysaccharides and acidic glycoproteins do not stain the same with all mucin techniques.
acidophillic
a basic (cationic, positively charged) substance that is easily stainable with acid dyes. An example is cell cytoplasm, which is readily stainable with the acid (anionic, negatively charged) dye eosin.
additive
a chemical or substance that adds on to, or combines with, another substance, usually improving, strengthening, or altering it. Many fixative molecules add on to tissue proteins, altering and stabilizing them in the process.
adeno-
a prefix denoting a relationship to a gland
adenoma
a benign tumor of epithelial tissue with glandular origin or characteristics, or both
adenocarcinoma
a cancer of epithelial tissue that has a glandular origin
adsorbtion
the accumulation of stain by the surface of a tissue component. this phenomenon is influenced by the affinity of oppositely charged ions for each other (electrostatic attraction or bonding)
aldehyde
an organic compound containing carbon, oxygen, and hydrogen arranged C=O and C-H
aliphatic hydrocarbon
organic chemical compound composed of carbon and hydrogen, in which the carbon atoms are linked in an open chain rather than a ring arrangement. Aliphatic hydrocarbons can be used as clearing agents
amphoteric
describes a substance that is capable of acting as either a base or an acid, depending on the pH of the solution
anaplasia
dedifferentiation, loss of cellular differentiation, or reversion to a more primitive form
angstrom
a unit of length equal to 100 millionths (10^-8) of a centimeter, or 10^-10 meters. This unit has been replaced by nanometer nm as the official unit of measurement. One nanometer is equal to 10A or 10^-9 meters
anion
a negatively charged dye or tissue component. Anionic substances are also referred to as acidic, although it has nothing to do with pH.
anisotropism
having unlike properties in different directions, or unequal in refracting power
anthracotic pigment
an accumulation of carbon from inhaled industrial pollution, cigarette smoke, or coal dust. The pigment is seen most frequently in the lungs or in lymph nodes from that area
antibody
commonly known as immunoglobulins, antibodies are proteins that are produced by B lymphocytes in response to antigenic stimulation
antigen
any substance that can induce a detectable immune response
antigen enhancement
epitopes can be exposed or “unmasked” by either heat or enzymes, thus enhancing the antigen-antibody reactivity
antigenic determinant
the area of an antigen that determines the specificity of the antigen-antibody reaction
apochromatic
corrected for both spherical and chromatic aberration. Apochromatic microscope objectives have been corrected for 3 colors and other lens aberrations
aqueous
a solution prepared in water
argentaffin
a reaction in which certain tissue components have the ability to bind or be impregnated with silver ions and then reduce the silver to its visible metallic form