hi let's talk about the bronchial tree
the bronchial tree consists of the trachea which sits inferior to the
larynx the primary or main stem bronchi the secondary bronchi the tertiary bronchi
and the bronchioles which branch from those tertiary bronchi
when we look at the division of the trachea into the primary bronchi we can see that there is
a ridge separating the right from the left main stem bronchi that ridge is called the carina
carina means keel as in the keel of a ship and so this this ridge is what's separating
air as it flows into the main stem bronchi it is very richly innervated and if anything were to
touch that carina or the mucosa of the carina an individual would immediately go into a fit of
bronchospasm and coughing to prevent any foreign bodies that had been inhaled that could trigger
that response from entering into the more distal portions of the pathway
now on the right here is an endocast which i think allows us to best visualize why this conductive
portion of the airway is referred to as the bronchial tree and it only takes a modest amount
of imagination to sort of turn this 180 degrees and see this would be the trunk of the tree and
all of the bronchi would be the branches of the tree now what you're actually looking at
is a posterior view of the endocast of the bronchial tree so here is the trachea
and the trachea is going to divide into right and left main stem bronchi also known as primary
bronchi these serve each lung the primary bronchi bifurcate into secondary bronchi on the right
and on the left trifurcate into secondary bronchi secondary bronchi serve lobes of the lung so these
are low bar bronchi and as there are three lobes typically to the left lung there should be three
secondary bronchi two lobes to the right lung two secondary bronchi on the right and then
the secondary bronchi give rise to the tertiary bronchi the tertiary bronchi as you may recall
serve bronchopulmonary segments and so there will be variable numbers of tertiary bronchi
supported by a secondary bronchus over here we can see some of the the lung parenchyma tissue
surrounding the the bronchial tree here and we have that would be a secondary
bronchus there's another secondary bronchus going into tertiary
bronchi tertiary tertiary tertiary there so we we really get a sense for how the parenchyma of the
lungs which is supporting the the alveoli and the respiratory bronchioles that support the alveoli
surround this bronchial tree thank you very much for your time