Final answer:
The upper airway warms, humidifies, and filters inhaled air through components like the nose, pharynx, and larynx. Option A is correct.
Step-by-step explanation:
The upper airway of the respiratory system has several key functions, including warming, humidifying, and filtering the air we breathe. The upper airway components include the nose, nasal cavity, pharynx, and larynx. Air enters through the nose where it is warmed to body temperature and humidified by mucus membranes. Particulate matter is removed by hairs, mucus, and cilia within the nasal cavity.
The pharynx acts as a passageway for both air and food. The larynx or 'voice box' is responsible for sound production, where air passing through the vocal cords generates speech. The epiglottis, a small flap, protects the trachea by preventing food from entering the windpipe during swallowing.
The trachea, which is part of both the upper and lower respiratory systems, serves as a funnel for inhaled air to the lungs and exhaled air out of the body. It is lined with mucus-producing goblet cells and ciliated epithelium, trapping foreign particles and moving them toward the pharynx. The hyaline cartilage rings provide structural support to keep the airway open. During a cough, the smooth muscle can contract, expelling mucus and foreign particles.
No gas exchange occurs in the upper respiratory tract; that function is reserved for the lower respiratory tract, specifically within the alveoli located in the lungs.
The trachea, part of both the upper and lower respiratory tracts, funnels air to and from the lungs and assists in expelling foreign particles through coughing. No gas exchange occurs in the upper airway; this process takes place in the lower respiratory tract's alveoli.