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let's first of all look at the different
portions of the lung there are two major
parts to the Airways a conducting
portion and then the respiratory portion
let's first of all look at the
conducting portion in this slide on the
right hand side you see three images one
is a section through the head region
showing you the oral cavity with the
tongue and the nasal cavity above it the
very circular like structure down on the
bottom right-hand side of this slide is
a section through the trachea you can
actually feel the trachea in your neck
you can feel the tracheal cartilages you
have about 16 to 20 of those cottages
that is a very important airway going
into the lungs and that is protected by
a structure called the epiglottis the
epiglottis sits just above the larynx
and it also sits right next to the entry
into the esophagus when we swallow if
you put your fingers around your trachea
or near your larynx and you swallow you
can feel the larynx moving upwards that
closes off the airway during swallowing
because the epiglottis is a elastic
cartilage flap that when you swallow and
the larynx is lifted it closes off
across that epiglottis and so food then
passes down the esophagus not down the
airways so they depa glottis is a very
important structure it's flexible
elastic cartilage line mostly by
stratified squamous epithelium because
it's wear and tear during swallowing but
also the very small component that sits
just above the larynx the entry into the
airway is lined by respiratory tract
epithelium we'll go to in more detail
later on in this lecture now the larynx
is our structure for speech production
and I'll go through that in more detail
at a later time
the bulk of the upper conducting portion
of the airway consists of the nasal
cavity and just the back the nasopharynx
and if we look at the nasal cavity just
above the area here it's important you
roughly know at this stage where it is
it's you can see a division between the
nasal cavity and the oral cavity that's
the hard palate and the soft palate
towards the posterior aspect
well when air passes down through the
trachea it passes through another series
of tubes called bronchi a single
bronchus is labeled here you can see a
couple of them in this section and also
some large blood vessels they too are
part of the conducting portion of the
respiratory tract and they will divide
as they go deeper down into the lung
into very small units called bronchioles
and that completes the conducting
portion of the lung now the importance
of this conducting portion is firstly to
warm the air and then to moisten the air
and then to clean the air of all any
inhaled debris we might happen to inhale
into our nasal cavity and we try to
prevent that from getting down into the
lungs so it's a very important function
of the conducting portion warm moisten
and clean the air
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you