What does the upper respiratory system consist of?

The upper respiratory system is defined as the portion of the respiratory system that is involved in the initial processes of air intake and filtration before it reaches the lower parts of the respiratory tract. This system consists of the nasal cavity, pharynx, and larynx.

The nasal cavity serves as the primary entry point for air, where it is filtered, heated, and moistened. Moving down the respiratory tract, the pharynx acts as a conduit for both air and food, facilitating the passage of air into the larynx, which is crucial for voice production and protecting the airway during swallowing. Each of these components plays an essential role in preparing air for entry into the lungs, where gas exchange occurs.

In contrast, the other components listed in the incorrect options belong to the lower respiratory system or do not fit into the definition of the upper respiratory tract. For instance, the bronchi and alveoli, while integral to the respiratory system, are located in the lower respiratory tract where gas exchange takes place. Similarly, the lungs and diaphragm are part of the mechanism responsible for breathing but also fall into the lower system. Lastly, the trachea, which is a major airway in the respiratory system, connects the upper and lower respiratory systems but