Final answer:
The trachea is the structure responsible for air conduction in the respiratory system, guiding air down from the pharynx towards the lungs, passing through the interconnected system of bronchi and bronchioles, to eventually reach the alveoli where gas exchange takes place.
Step-by-step explanation:
The structure that plays a role in air conduction is the trachea. When we breathe in, air travels from the pharynx to the trachea, passing through the bronchi and bronchioles, and eventually reaching the lungs. The trachea and other parts of the lower respiratory tract, such as the bronchi and bronchioles, are mainly responsible for the conduction of air. These structures are made of cartilage and smooth muscle and are innervated by the nervous system, which controls their contraction and relaxation. Unlike these air-conducting pathways, gas exchange occurs in the alveoli, which are small, grape-like sacs at the end of the alveolar ducts.