Which of the following best describes the primary difference between the conducting zone and the respiratory zone of the respiratory system?

• A. The conducting zone transports air to the lungs but does not participate in gas exchange, while the respiratory zone is where gas exchange occurs between air and blood.
• B. The conducting zone is responsible for oxygenating blood, while the respiratory zone filters and humidifies incoming air.
• C. The conducting zone is found only in the upper respiratory tract, while the respiratory zone is found only in the lower respiratory tract.
• D. The conducting zone includes the alveoli, whereas the respiratory zone consists only of the trachea and bronchi.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the structure and function of the respiratory system. The respiratory system is divided into two main zones: the conducting zone and the respiratory zone. Each has distinct roles in the process of respiration.
2. Step 2: Define the conducting zone. The conducting zone includes structures such as the nose, pharynx, larynx, trachea, bronchi, and bronchioles. Its primary function is to transport air to the lungs, filter, warm, and humidify it, but it does not participate in gas exchange.
3. Step 3: Define the respiratory zone. The respiratory zone includes structures such as the respiratory bronchioles, alveolar ducts, and alveoli. This is the site where gas exchange occurs between the air and the blood, facilitated by the thin walls of the alveoli and the surrounding capillaries.
4. Step 4: Compare the roles of the conducting zone and the respiratory zone. The conducting zone is responsible for air transport and conditioning, while the respiratory zone is specialized for gas exchange. This distinction is the primary difference between the two zones.
5. Step 5: Evaluate the options provided in the problem. Use the definitions and comparisons above to identify the correct description of the primary difference between the conducting zone and the respiratory zone.