Final answer:
Air enters through the nasal cavity where it is filtered and moistened. It then passes through the pharynx and larynx, where the epiglottis prevents food from entering the trachea. Finally, the air reaches the trachea and travels into the lungs for gas exchange.
Step-by-step explanation:
The process of air traveling through the respiratory system involves several structures. From the nasal cavity, air is filtered, warmed, and moistened before passing into the pharynx (throat), which is a shared pathway for both air and food. The air then moves into the larynx (voice box), responsible for vocal sound production as air causes the vocal cords to vibrate.
A crucial protective mechanism here is the epiglottis, a flap that covers the trachea during swallowing to prevent food from entering the lungs. Once past the larynx, air enters the trachea (windpipe), a cylinder supported by cartilage rings that ensure it remains open. The trachea then directs the air into the lungs where gas exchange occurs in the alveoli.