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hello everyone in this video we're going
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to be continuing with the respiratory
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system discussing the trachea and lungs
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so friendly reminder from our earlier
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respiratory system videos is that now we
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are moving into the lower respiratory
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system so the upper respiratory system
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was everything above the vocal folds in
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the larynx and everything below the
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vocal folds is classified as the lower
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respiratory system okay so that's what
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we'll be discussing today so I can get a
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little a note so that would be right
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about here okay where your vocal folds
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would be located just a little inferior
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to your laryngeal prominence so when the
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air comes past the larynx
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so there's your cut off for the larynx
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okay so here's your quick loyd cartilage
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right here the air from the external
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environment so it came in through your
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mouth and nose and is now moving down
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the trachea hey
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the trachea is fairly solid tube it is
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formed by many cartilaginous rings so
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that's what you see here and they are
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connected by ligamentous membranes and
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otherwise it's just a hollow tube at the
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level right here of the sternal angle
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okay so the sternal angle if you recall
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from much earlier in the semester is
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where the manubrium meets the body of
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the sternum okay and then your xiphoid
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process would be here so when you're
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looking your sternum you have the
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manubrium here the body of the sternum
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here and then xiphoid process at the
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bottom that's an X the sternal angle is
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right there okay so it's where the body
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meets them in rhea and that's the point
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at which your trachea is going to
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bifurcate or slit in the tube and that
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location is called the Carina okay
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that's the name of the spot where the
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trachea bifurcates or divides into two
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it's going to divide into two primary
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bronchi okay so you have your right main
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or primary bronchus which is the sky and
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then your left primary bronchus or left
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main bronchus which is there okay from
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there our main bronchi are going to
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divide into low bar bronchi so what that
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means is that each lung has a certain
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number of lobes and each lobe get its
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own gets its own bronchi okay so in the
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right lung we have three low bar bronchi
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Hey um and you can't see mom there's one
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in the back okay so there's three on the
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Left there's two because there's only
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two lobes there's only two lobes in the
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left lung and we'll look at the lungs a
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little more closely later okay now a few
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things that are worth noting the oops so
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we said that there are three low bar
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bronchi on the right so there's your
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spelling by the way lobar bronchus
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bronchus is singular if you replace the
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US with an eye you have bronchi which is
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plural okay and then left lobar bronchus
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okay so we have three on the right and
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two on the left and that's because they
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match the number of lobes in each limb
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okay you'll also notice the right lung
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is larger than the left lung and that's
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because the left lung has to accommodate
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the heart which cheats a bit to the left
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okay so the heart would be kind of in
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here and that's going to take up some
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left lung space so the left lung is
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smaller and some thing I want to point
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out about the main bronchi before we
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move on is that your right main bronchi
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points more inferior leak so kind of
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points more straight down compared to
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the left bronchus the left main bronchus
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which is a little more horizontal now
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this is important from a clinical
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perspective the
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excuse me even though we have all of
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these cilia and the mucous membranes and
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all these ways of keeping foreign
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particles out of the lungs if something
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does sneak down a little virus or
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whatever when it gets to the Carina
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because the paps into the right lung is
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a little more of a straight down pathway
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your right lung is much more likely to
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get foreign bodies in it so if you are
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going to get a viral infection or
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something like that that came in through
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your trachea it's more likely to go into
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the right lung than the left only
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because the pathway into the right main
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bronchus is just a little bit straighter
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versus on the left you have to make sort
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of a more of a hard turn okay so kind of
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an interesting interesting loaf in fact
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now our lobe our bronchi are going to
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keep dividing okay and you can see that
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here so they divide into smaller bronchi
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and then eventually into smaller tubes
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called bronchioles okay and you have
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here your branching over here nice
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helpful chart so the trachea splits into
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two main bronchi those divide into the
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Lubar bronchi so you have three on the
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right and two on the left then those
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divided into a number of segmental
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bronchi those divided into bronchioles
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and then those divided into what's
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called terminal bronchioles which are
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the last ones when we get the end of the
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terminal bronchioles we go right right
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down to very tiny tubes called
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respiratory bronchioles okay and these
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are now getting into the alveoli okay
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I'm not fussed about the specifics here
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but they're there if you want the detail
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so basically I don't need you to know
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the names of anything beyond the lobar
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bronchi okay I do want you to know the
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lobar bronchi beyond that just there's
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more divisions to smaller bronchi than
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bronchioles and eventually to the
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alveoli
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okay so here's your alveoli it looks
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like they look like little clumps of
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grapes and they're just very thin walled
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sacks okay and this is where gas
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exchange is going to take place within
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the lungs so what we have here is in red
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you have a branch of pulmonary vein and
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in blue we have a branch of pulmonary
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arteries
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okay keeping in mind that these are the
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opposite from systemic arteries and
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veins
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okay so pulmonary arteries are very high
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in oxygen pulmonary veins
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sorry pulmonary arteries are very low in
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oxygen pulmonary veins are very high in
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oxygen and that's why the colors are
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switched here from what you're used to
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seeing so the branches of the pulmonary
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arteries and veins are going to be very
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very close to all of these alveolar sacs
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okay so they're gonna form tiny
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capillaries so all your pulmonary veins
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um sorry the pulmonary let's erase this
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so that you can have a better view okay
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good so pulmonary arteries are going to
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leave the right ventricle of the heart
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branch branch branch branch the oxygen
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amount in them is low which is why
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they're blue and they're gonna branch
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until we get to these little capillary
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beds that surround each alveoli and at
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this point the carbon dioxide and waste
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products that are in the pulmonary
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arterial are going to cross into the
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alveoli okay so they're gonna go in here
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and all the oxygen that we got from the
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environment is going to go out into the
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blood okay and then the pulmonary veins
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will carry that nice oxygenated blood
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back to the left atrium okay
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all right let's zoom in and look at the
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lungs themselves now very similar to the
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heart the lungs are covered in a pleural
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serous membrane that has two layers okay
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so we have an outer layer which is
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called the parietal pleura and the inner
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layer right up against the lungs which
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called the visceral pleura and between
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the two we have a little space called
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the pleural cavity okay and you can see
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the pleural cavity especially down at
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the bottom this is where the most space
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tends to be and the pleural cavity is
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there because when you breathe in so
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when you take a deep breath in all that
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empty space will fill with the lungs and
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then when you breathe out the pleural
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cavity will have a lot of emptiness
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again okay so the pleural cavity is
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providing space for the lungs to expand
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into these are again serous membranes
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which means they produce serous fluid so
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that there isn't friction when they rub
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against each other okay the primal plant
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flora and the visceral pleura meet each
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other so they come together at the root
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of the lungs okay and I'll show that to
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you in a later image we can't really see
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it here so they're going to connect to
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one another at the root of the lungs and
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it's not this picture oh it's this one
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and we'll go back to the one I just okay
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so the root of the lungs this is an
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medial view
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okay so you've opened up the lungs and
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you're looking at the surface of the
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lungs that would that would face the
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heart okay that's what we're looking at
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in this image so the root of the lungs
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is where a collection is a collection of
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structures that enter and leave the
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lungs and it's the location where the
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bridal and visceral pleura need each
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other okay
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that spot on the lungs so if we take out
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all the stuff um the actual area of the
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lung where the root is is called the
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hilum okay so I'll give you some nice
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definitions because I know you like
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those so the hilum know let's start with
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the root the root is a collection of
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structures that enters and leaves the
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lungs okay so that will include the the
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main bronchi or possibly the lobar
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bronchi if they're already slipped by
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this point it sort of depends on the on
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the lung of the person the pulmonary
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artery
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and the pulmonary veins okay so put all
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those things together and you get the
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root of the lung the hilum is the the
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spot on the lung where those things come
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in and out okay so I'm gonna back one
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because I want to talk a little bit more
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about each specific loan so we mentioned
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that the right lung is larger than the
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left because the left has to accommodate
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for the heart taking up space on that
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side so the right lung the right lung as
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we mentioned has three lobes okay so the
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superior lobe is there the middle lobe
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is here and then the inferior lobe is
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here okay and they're divided by what
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are called fissures so the oblique
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fissure divides goes like this so it
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splits the superior from the inferior
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lobe it also divides the middle from the
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inferior lobe okay and then we also have
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a horizontal fissure
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right here and that divides the superior
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and middle lobes okay on the Left we
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only have two lobes the superior lobe
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and inferior lobe and they are divided
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by the oblique fissure okay so what
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you're looking at here is a lateral view
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of the lung so this is the side that
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would face outwards to the ribs and then
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again this is our medial view so this is
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the the surface of each lung that would
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face the heart and you can actually see
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that there's that it's kind of squashed
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in here that's called the cardiac
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compression so that's where the heart is
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okay and you can also see little
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markings from other big blood vessels
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and stuff like that that are there
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running by okay I'm not worried about
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you knowing what each one is but in case
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you're curious the ones are very squashy
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so you do see markings on them from more
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solid structures that are nearby okay
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and we are going to wrap it up there
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today I will see you next time
