01 / Location & anatomical relationships
Branching from the trachea into the right and left lungs.
02 / Structure & organization
Main bronchi enter the lungs and branch into lobar and segmental bronchi. Cartilage and smooth muscle support the larger conducting airways. Smaller bronchioles lack cartilage and lead toward respiratory portions of the lung.
03 / Function
They divide into smaller passages inside your lungs.
04 / Mechanism
Each main bronchus enters a lung and divides repeatedly. Smaller bronchi lead to bronchioles and eventually to air sacs. Supporting tissue and airway muscles help maintain and adjust the passages.
Working together: respiratory system
Your diaphragm contracts to help draw air in. Air reaches your lungs, where oxygen crosses into the blood through the walls of tiny air sacs.
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Connect structure with function
Airway resistance changes with caliber. The right main bronchus is generally wider, shorter and more vertical than the left, an important spatial distinction.
Check your understanding
Locate the bronchi in relation to its neighbors. Explain how the structural features described above support its function, then distinguish it from a nearby structure with a different role.
Keep learning
Continue with OpenStax Anatomy and Physiology for system-level study. This atlas is educational and has not undergone independent medical peer review.