How many main bronchi are there in the human body?

A bronchus is a passage or airway in the respiratory system that conducts air into the lungs. The first bronchi to branch from the trachea are the right main bronchus and the left main bronchus, also known as the primary bronchi. These are the widest and enter the lungs at each hilum, where they branch into narrower secondary bronchi or lobar bronchi, and these branch into narrower tertiary bronchi or segmental bronchi.

Further divisions of the segmental bronchi are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi. The bronchi when too narrow to be supported by cartilage are known as bronchioles. No gas exchange takes place in the bronchi.

More Info: en.wikipedia.org

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18 Comments

Carolyn Brior

I guess David was counting the primary bronchi only

bonniecardona

There are 2 bronchi in each lung so to me that means there are 4 in the human body which is what the question asked not how many in each lung!!!

earlepg

Figured that bronchi was plural and related to the lungs, hence either 2 or 4: chose 2.

james parrillo

tbear, I am sorry you were not aware of this. Biology was one of the subjects, like geometry, that I could picture. After I answered the question, I searched for diagrams of the lungs and trachea. They show the trachea as a long tube, dividing at the bottom into two, on the left and the right. These are the bronchi heading to the lungs. I always loved biology vocabulary too, to the extent I had it, so I was waiting to see if the author would mention the much smaller bronchioles. I never entered a medical field. I think the accompanying math requirements would have been too much. Thank you, Christine, James's wife