hi let's talk about the structure and function of the respiratory system in this video we'll
discuss the gross features and regions as well as the functions of the respiratory system
so the respiratory system consists of a conducting pathway to bilaterally paired lungs
so that conducting pathway begins with the nose and mouth that feed into nasal and oral cavities
those then are going to feed into the pharynx or the throat which is a common aerodigestive
pathway so the respiratory system as well as the digestive system shares this pathway an
exclusively respiratory part of the pathway is the larynx or voice box which sits atop the trachea
the windpipe that trachea bifurcates into primary bronchi that are part of the bronchopulmonary tree
they're going to divide into secondary bronchi and then into tertiary bronchi and then into
various types of bronchioles that eventually are going to support alveoli within the lungs
where gas exchange occurs so there are a couple of ways in which we can divide
the respiratory system to to conceptualize it the first is anatomically so
anatomically we can divide the respiratory system into the upper and the lower respiratory system
so the upper respiratory system consists of all of the conductive pathways
down to the vocal folds of the larynx so the larynx or the voice box is right there the
vocal folds sit between the arytenoid cartilage and the thyroid cartilage and so everything
proximal to the vocal folds is the upper portion of the respiratory system everything distal to
the vocal folds is the lower portion of the respiratory system so if you have a head cold
that would be an upper respiratory infection if you have something that has manifested itself
down in you know your chest you can feel it rumbling there that would be a lower respiratory
infection we can also divide up this physiologically by zones so there is a conducting
zone and a respiratory zone the conducting zone is for pushing air the respiratory zone is for
moving gases in and out of the cardiovascular system and so that boundary between the two
is found within the bronchioles where the distal part of the conducting zone are the terminal
bronchioles
whereas the proximal part of the respiratory zone are the
respiratory bronchioles
so all the hints to remember where they are are within the name so the terminal bronchioles
are the termini of the conducting zone the respiratory bronchioles are
of the respiratory zone how wonderful let's discuss function number one with a bullet
is going to be gas exchange so we are complex organisms we have very
metabolically active tissues our need for energy to power endergonic cellular
activities is high and so in making a lot of atp we're going to need a lot of
oxygen that's the terminal proton acceptor and chemiosmosis
and we're also going to generate a lot of carbon dioxide as a metabolic byproduct of
cellular respiration which we're going to need to eliminate so these will be carried
you know to and from metabolically active tissues by the cardiovascular system the cardiovascular
system interplays with the respiratory system so that these gases can be exchanged with the
atmosphere around us you know and as part of that process the respiratory system is going to play a
vital role in helping to maintain ph homeostasis within the cardiovascular system so if you recall
the carbonic acid bicarbonate ion buffer system so there are these dynamic equilibria
between various molecules so carbon dioxide and water are in a dynamic equilibrium with
carbonic acid h2co3 which is in a dynamic equilibrium with bicarbonate ion
and protons and so as blood is more acidic or if it were to become
more acidic that's going to shift the equilibrium of the equation to the left and
produce more carbon dioxide and the respiratory system can compensate
for that by increasing the rate of respiration by increasing the rate of respiration you can
excrete more carbon dioxide from the body likewise if uh it's more of an alkaline environment
an individual may decrease their rate of respiration they can even hold their breath
to help shift the equation to the right so the respiratory system and the cardiovascular system
have a lot of interplay here the respiratory system is also very important for the production
of sound and vocalization this is going to be largely a function of the larynx
as we'll discuss but there are other features along that pathway which can can help
shape that sound and then finally along the superior portion of the
nasal cavity there is respiratory epithelium which is rich with the olfactory nerves and so olfaction
is another function of the respiratory system that we should all be very grateful for
and that leads us to our assessment question of the video and that is
pharyngitis this is an inflammation of the pharynx in other words a sore throat is a common symptom
of what type of respiratory infection is it a lower respiratory infection or an
upper respiratory infection well recall the relationship between the pharynx
which kind of looks like that and the larynx which kind of looks like that
the nasal cavity and the oral cavity and we can see that
the pharynx is more proximal than the larynx and within the larynx where we have those vocal folds
everything proximal to the vocal folds is the
upper respiratory everything distal to the vocal folds is the lower respiratory
and so a pharyngeal
infection is going to be an upper respiratory infection auri thank you very much for your time