Glossary

Author: Glossary

  • Umbrella filter

    A filter placed in a blood vessel to prevent emboli from passing that point. It has been used in the vena cava to prevent emboli in the veins from reaching the lungs.  

  • Pasteur-Chamberland filter

    An unglazed porcelain filter capable of retaining bacteria and some viruses. Either pressure or suction is required to force or draw the liquid through the filter.  

  • Optical filter

    A device that passes only a portion of the visible light spectrum. Absorption filters absorb the unwanted wavelengths. Interference filters employ the wave effects of constructive and destructive superposition to pass or inhibit appropriate wavelengths.  

  • Membrane filter

    A filter made from biologically inert cellulose esters, polyethylene, or other porous materials.  

  • Infrared filter

    A filter that permits passage of only infrared waves of a certain wavelength.  

  • High efficiency particulate air filter

    An air filter capable of removing 99.7% of particles greater than 0.3 μm in diameter.  

  • Compensating filter

    In radiography, a filter that shields less dense areas to produce a more nearly uniform radiographic image.  

  • Filovirus

    A family of encased, negative-stranded RNA viruses that can cause fatal hemorrhagic fevers. They include Marburg and Ebola viruses.  

  • Filopodia

    Bundles of actin filaments that project from the cell surface.  

  • Film speed

    The sensitivity of a photographic medium (e.g., a radiograph) to light or radiation. The film speed is determined by: the size of its silver halide crystals; the thickness of the emulsion; and the presence of radiosensitive dyes. In radiography, the term “speed” denotes the comparative degree of darkening produced on a film, taking into consideration…