hi let's talk about the trachea the trachea is a tube that connects the lyrics to the bronchi
or the primary bronchi so as we can see here here's the legs with the the thyroid cartilage
that's been reflected away here's our cricoid cartilage and then extending down contiguously is
this fibro and hyaline cartilaginous tube with hyaline cartilage C shaped rings that run the
length of the tube so the the inferior margin of the lyrics is about c6 where the primary bronchi
bifurcate is about t4 or t5 so that's about at the sternal angle so the the boundary between
the superior mediastinum and the remainder of the mediastinum there are approximately 16 to
20 of these C shaped hyaline cartilage rings if we were to look posteriorly over on the left hand
side here we can see there's the bottom of the cricoid cartilage and there's probably our our
first cartilaginous ring there anteriorly and between the two all the way around is the crico
tracheal ligament and this is just the connective tissue that attaches the cricoid cartilage and the
remainder of the lyrics to the trachea so if we were to take two transverse sections and remove a
piece we would be left with what we're seeing here this is a posterior view and we can see there are
the hyaline cartilage rings those see shapes as they extend about that hyaline cartilage helps to
maintain the patency of the the airway those are the the tracheal cartilages and then the posterior
aspect of the the trachea is a fibromuscular membrane and that fibromuscular membrane if we
look at it from an anterior view so here's a view of a section of the trachea where those
tracheal cartilages have been incised and then reflected out laterally we could see that there
are various ridges that arise from the mucosa of the trachea the the tracheal mucosa is very
rich with with mucous glands but contained in this section here in particular that that I'm outlining
so that that posterior fiber muscular membrane is trachealis muscle trachealis muscle is
smooth muscle so it's under autonomic control and this trachealis muscle can contract in order to
decrease the size of the lumen of the airway or relax in order to increase the size or the
patency of the airway and so that the trachea is an important structure because it is the conduit
between the larynx and the remainder of the the aerodigestive pathway and the the bronchial system
which is going to conduct air to and from the lungs thank you very much for your time