What is the point in the respiratory track where inspired gas reaches body temperature, ambient pressure, saturated (BTPS) conditions?

Question

Quizplus · Accepted Answer

As inspired gas moves into the lungs, it achieves BTPS conditions (body temperature, 37° C; barometric pressure; saturated with water vapor [100% relative humidity at 37° C]). This point, normally approximately 5 cm below the carina, is called the isothermic saturation boundary.

What Is the Point in the Respiratory Track Where Inspired