Which structures branch off the trachea into the lower airway?

The bronchi are the structures that branch off the trachea into the lower airway. When air is inhaled through the trachea, it travels down to the primary bronchi, which then further divide into secondary and tertiary bronchi that supply each lung. This branching system is essential for delivering air to the lungs, where it can participate in gas exchange.

The distinction between the bronchi and other structures is critical. Alveoli are the tiny air sacs where gas exchange occurs, but they are located at the end of the airway and are not direct branches of the trachea. Bronchioles are smaller air passages that stem from the bronchi, but they come after the bronchi in the airway. Capillaries are the small blood vessels involved in the exchange of oxygen and carbon dioxide but are not part of the airway structure itself. Understanding the anatomy and flow of air through these components is vital for comprehending respiratory physiology and airway management.