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Bronchi

The branching airways that carry air from the trachea into the lungs.

The respiratory tract From the upper airway down through larynx, trachea and bronchial branching into the two lungs, with the diaphragm at the base. A separate inset shows alveoli — the microscopic gas-exchange sacs inside the lungs. Each label links to the article for that part. Alveoli Upper respiratory tract Larynx Trachea Bronchi Lungs Diaphragm The respiratory tract — schematic, not to scale.

The trachea splits into two main bronchi, one per lung, which divide again and again into ever-smaller branches — the “bronchial tree” — ending in tiny bronchioles.

  • Conduct air deep into the lungs.
  • Adjust airflow — the smallest bronchioles can widen or narrow.
  • Continue cleaning the air with mucus and cilia.

The bronchial tree is a distribution network — repeated branching spreads incoming air across the lungs’ enormous internal surface.