Here is a sample of the answers for Chapter 38 of the Egan’s Workbook. For rest of the answers, check out our Workbook Helper. We have both the 10th and 11th Edition available.

  1. Hygrometer: an instrument used for measuring the moisture content in the atmosphere. Humidity measurement instruments usually rely on measurements of some other quantity such as temperature, pressure, mass or a mechanical or electrical change in a substance as moisture is absorbed.
  2. BTPS conditions: body temperature and pressure, saturated; denoting a volume of gas saturated with water vapor at 37°C and ambient barometric pressure.
  3. Isothermic saturation boundary: the point at which inspired gas reaches body temperature and is fully saturated (44 mg H2O/L at 37°C). This normally occurs around 5 cm below the carina.
  4. Inspissated: thickened secretions.
  5. The nose is the bodies natural humidifier and filter, when bypassed we must use a artificial humidifier. The respiratory tract warms and humidifies inspired gases such that alveolar gas is at BTPS (body temperature, atmospheric pressure and saturated with water vapor). The point at which gases reach 37° C and 100% relative humidity (absolute humidity of 44 mg H2 O/L) is known as the ‘‘isothermic saturation boundary’’. Humidity and temperature are constant below the ISB, while above the ISB, the airway acts as a countercurrent heat and moisture exchanger. During hyperventilation or the breathing of cold, dry air, the ISB moves down the bronchial tree forcing the lower respiratory tract to aid in heat and moisture exchange.


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