Which structures comprise the upper respiratory system?

• A. Larynx, trachea, bronchi
• B. Nose, nasal cavity, paranasal sinuses, pharynx
• C. Larynx, trachea, bronchioles
• D. Pharynx, larynx, trachea, lungs

Answer: (B)

The upper respiratory system consists of structures that primarily conduct and condition air before it reaches the lungs: the nose, nasal cavity, paranasal sinuses, and pharynx. These components filter, humidify, and warm or cool the incoming air and also host parts of our sense of smell. The larynx, trachea, bronchi, and bronchioles are downstream in the airway and form the lower respiratory tract where air reaches the bronchioles and alveoli for gas exchange. Therefore, the set including the nose, nasal cavity, paranasal sinuses, and pharynx best fits the upper respiratory system.