

The larynx aids phonation and conducts the gas into the trachea which in an adult is about 18mm in diameter and 11 cm in length. The nose, mouth and pharynx conduct air to the larynx, humidify and filter the air gases.

To maintain gas exchange function, the anatomy of the respiratory system is designed in such a way to make the process as efficient as possible.

Fowlers method measures physiological dead space.The answers can be found at the end of the article, together with an explanation. Before continuing, try to answer the following questions.
