Which sequence correctly describes the path of inhaled air from the mouth to the lungs?

• A. Mouth, Pharynx, Trachea, Larynx, Bronchi, Bronchioles, Alveolar Sacs
• B. Mouth, Pharynx, Larynx, Trachea, Bronchi, Bronchioles, Alveolar Sacs
• C. Mouth, Pharynx, Larynx, Esophagus, Bronchi, Bronchioles, Alveolar Sacs
• D. Mouth, Pharynx, Larynx, Trachea, Bronchi, Alveolar Sacs, Bronchioles

Answer: (B)

Air travels through a clear sequence of airways that become progressively narrower until it reaches the sites of gas exchange. Starting at the mouth, the air moves into the pharynx, then through the larynx, down the trachea, and into the bronchi. From there it continues into the bronchioles and finally ends at the alveolar sacs where oxygen moves into the blood and carbon dioxide is released.

This order matches how the respiratory tree is organized: the larynx is the gateway between the upper and lower airways, the trachea conducts air into the lungs, the bronchi branch within the lungs, bronchioles are the tiny passages that lead to the alveolar sacs, and the alveolar sacs are the end points for gas exchange. The esophagus is not part of the inhaled air path, which is why a sequence including it isn’t appropriate, and reversing the order of bronchioles and alveolar sacs would place gas-exchange structures in the wrong place.