Question: 165: Which of the following is not the function of conducting part of respiratory system?
(1) Temperature of inhaled air is brought to body temperature
(2) Provides surface for diffusion of \mathrm{O}_{2} and \mathrm{CO}_{2}
(3) It clears inhaled air from foreign particles
(4) Inhaled air is humidified
Answer: Option (2)
Explanation:
The conducting part of the respiratory system includes the nasal cavity, pharynx, larynx, trachea, bronchi, and bronchioles. Its main function is to transport air to and from the lungs.
During this process, the inhaled air is warmed to body temperature, humidified,
and cleaned of dust and foreign particles by mucus and cilia.
Diffusion of respiratory gases occurs only in the respiratory part of the lungs, mainly in the alveoli,
where a thin membrane and rich blood supply are present.
Therefore, providing a surface for diffusion of
\mathrm{O}_{2} and \mathrm{CO}_{2}
is not a function of the conducting part of the respiratory system.