#plethysmograph  a measuring instrument for measuring changes in volume of a part or organ or whole body (usually resulting from fluctuations in the amount of blood it contains)
  supertype:  measuring_instrument__measuringinstrument__measuring_system__measuringsystem__measuring_device__measuringdevice  instrument that shows the extent or amount or quantity or degree of something
  subtype:  body_plethysmograph  plethysmograph consisting of a chamber surrounding the entire body; used in studies of respiration
  subtype:  digital_plethysmograph__digitalplethysmograph  plethysmograph applied to a digit of the hand or foot to measure skin blood flow

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