Which of the following structures is NOT considered part of the upper airway?

The trachea is not considered part of the upper airway because it is the structure that connects the upper airway to the lower airway, where the lungs are located. The upper airway is composed of all the structures above the larynx, which includes the nose, mouth, pharynx, and epiglottis. The function of the upper airway is primarily to filter, warm, and moisten the air we breathe before it reaches the lower airway and the lungs. Understanding this distinction is crucial in emergency medical situations, as interventions and assessments are often specific to the upper or lower airway.