Glossary

Author: Glossary

  • Arterial duplex ultrasonography

    A diagnostic procedure that helps to identify areas within arteries where blood flow is blocked or reduced.  

  • Ultrasonics

    The division of acoustics that studies inaudible sounds, i.e., those with frequencies greater than 20,000 cycles/sec (20,000 Hz or 20 kHz). Biological effects may result, depending on the intensity of the beams. Heating effects are produced by beams of low intensity, paralytic effects by those of moderate intensity, and lethal effects by those of high…

  • Ultrarapid

    Exceptionally fast; said of, e.g., centrifuges, some chemical reactions, and some forms of tissue fixation or freezing.  

  • Ultrafilter

    A filter by which colloidal particles may be separated from their dispersion medium or from crystalloids.  

  • Ultradian

    Concerning biological rhythms that occur less frequently than every 24 hr.  

  • Ultracentrifugation

    Treatment or preparation of substances by use of the ultracentrifuge. Analytical ultracentrifugation is a means of determining molecular mass, structure, and size. Preparative ultracentrifugation is a means of purifying mixed solutions of proteins. It separates them based on their densities or their sedimentation coefficients.  

  • Ultimobranchial body

    One of two embryonic pharyngeal pouches usually considered as rudimentary fifth pouches. They become separated from the pharynx and incorporated into the thyroid gland, where they give rise to parafollicular cells that secrete calcitonin, a hormone that lowers the blood calcium level.  

  • Ulmus fulva

    The scientific name for slippery elm. Also known as Ulmus rubra.  

  • Ulerythema ophryogenes

    Folliculitis of the eyebrows, characterized by loss of hair and scarring.  

  • Ulerythema

    An erythematous disorder with atrophic scar formation. A dermatological condition marked by scarring.