0:02 hi everybody dr mike here in this video
0:03 we're going to take a look at parts of
0:14 [Music]
0:16 now we're going to follow the pathway of
0:18 air from being inspired from the outer
0:20 atmosphere all the way down into our lungs
0:20 lungs
0:21 and have a look at some of the major
0:23 anatomical compartments
0:26 or structures that that air needs to
0:28 move through what we call the conducting pathways
0:29 pathways
0:31 first of all when air is first inspired
0:33 it enters something called
0:41 now once it enters the nasal cavity it
0:43 moves to the back of the throat
0:45 and that area we call the pharynx and
0:46 there's actually three parts to the pharynx
0:47 pharynx
0:49 so i'm going to highlight this entire
0:50 area here
0:57 now sometimes we can inspire air through
0:58 the mouth and so obviously
1:00 that's going to go through the oral
1:03 cavity now with the pharynx we've got
1:04 the nasal portion
1:06 which we call the nasopharynx we've got
1:08 the oral portion which we call the oropharynx
1:09 oropharynx
1:11 and we've got the next portion here
1:13 called the larynx
1:14 and this part of the back of the throat
1:16 just where the larynx is is called the
1:19 laryngo pharynx which means that the
1:20 next component
1:27 now what we've just highlighted here
1:29 from the nasal cavity to the three
1:30 aspects of the pharynx
1:32 to the larynx is what we call the upper
1:37 now this is important clinically because
1:39 you've heard of upper and lower
1:40 respiratory tract
1:41 infections so obviously upper
1:43 respiratory tract infections
1:46 involve these anatomical components so
1:47 what do lower respiratory tract
1:49 infections refer to well
1:58 air passes through the trachea and then
2:00 the trachea splits
2:02 and this is known as a bifurcation it bifurcates
2:03 bifurcates
2:06 left and right and once it bifurcates it
2:07 turns into the left
2:10 and right main stem like the stem of a tree
2:11 tree
2:13 bronchi so these are called bronchi so
2:14 i'm just going to label one but we know
2:21 now these bronchi will continue to
2:24 branch and they branch around about 23
2:27 different times and what you'll find is
2:28 that these various branchings
2:31 these various branchings result in on
2:32 the right hand side
2:36 three lobes of the lungs upper
2:39 middle lower or superior middle inferior
2:42 and on the left side two lobes upper
2:45 lower superior inferior now you
2:47 the question probably is why three on
2:48 this side and why two on this island's because
2:49 because
2:52 there's a little cut out of the lungs
2:52 that you can see
2:54 here and this is called the cardiac
2:56 notch because
2:58 our heart sits a little bit to the left
3:00 and we need to make room for the heart
3:02 so there's a little bit less lung on the
3:04 left hand side and therefore
3:06 less room for lobes and so there's only
3:07 two lobes on that side
3:09 when we look at the bronchi an important
3:11 point is that the right stem bronchi
3:13 which you can see here
3:16 is wider and more vertical which is
3:18 important clinically because if some
3:21 substance or object is inhaled it's most
3:23 likely to be found in the right stem
3:24 bronchi now
3:26 after these bronchi like i said branch
3:28 about 23 separate times they go into smaller
3:29 smaller
3:32 bronchioles and then they start to turn into
3:33 into
3:36 alveoli and alveoli are the site of gas exchange
3:44 now trachea bronchi
3:46 and the lungs which include the alveoli
3:48 this is the lower
3:54 again very important clinically now
3:55 let's have a look at let's start back up
3:57 here and work our way down and look at
3:58 some important points firstly
4:00 in the nasal cavity there are these
4:02 various folds called
4:04 turbinates now these turbinates are
4:05 really important because they're lined by
4:06 by
4:08 mucus and a lot of blood vessels and
4:10 what these turbinates do is when we
4:11 inspire gas
4:14 when we spy that air from the atmosphere
4:16 it spins the air around the air goes in
4:18 these through these turbinates and it
4:18 spins them
4:22 right now what this does is it throws
4:23 all the particulates that are in that gas
4:24 gas
4:26 so maybe pathogens or pollutants or
4:27 whatever it may be
4:30 and they stick to the mucus which means
4:31 we do not inspire
4:34 any of these horrible things down into
4:34 our lungs
4:36 the other thing is because there's a lot
4:38 of mucus and blood vessels
4:42 it warms that air up and it humidifies
4:44 that air which is great because it makes
4:46 gas exchange at the alveoli
4:49 more beneficial next thing
4:51 we go back to the pharynx like i said
4:53 nasopharynx laryngeal
4:55 oral pharynx and laryngeal pharynx and
4:56 then we move down to the larynx now the larynx
4:57 larynx
4:59 is our voice box this is where we have
5:01 our vocal cords and you know where the
5:03 larynx is because of the
5:05 adam's apple now this is termed the
5:07 laryngeal prominence
5:10 and it's simply cartilage and both males
5:11 and females
5:14 have an adam's apple important point
5:16 now you can also feel that there is a
5:18 underneath the laryngeal prominence
5:19 there is a soft
5:22 portion here and this portion is very
5:23 important as
5:25 an accessory airway if the airway is blocked
5:26 blocked
5:28 superiorly as we move down to the
5:30 trachea you can see there's a lot of cartilage
5:31 cartilage
5:33 lining the trick here and this keeps it
5:34 open the term we use is
5:36 patent think about sipping through a
5:38 straw if you take a straw and put your
5:39 finger on the end
5:41 and suck on it the straw collapses
5:43 because there's a negative pressure you
5:45 take all the air out so the pressure is
5:47 negative inside that straw
5:48 now same thing would happen in the
5:50 trachea because air moves in and out
5:52 simply due to pressure changes so we
5:53 have cartilage
5:55 lining the trick here to keep it strong
5:57 and open
6:00 now as we move through from the trachea
6:02 through to the bronch bronchi through to
6:03 the smaller bronchioles
6:07 the the amount of cartilage diminishes
6:09 and the amount of muscle increases which
6:10 then means that
6:13 as we move through these smaller airways
6:14 this is where
6:16 muscle plays an important role and they
6:17 can open and close because that's what
6:18 muscle does
6:20 it relaxes and constricts and this is
6:22 important clinically
6:24 because asthma is a disease of the
6:26 bronchioles where the smooth muscle is
6:29 because it constricts it's not a disease
6:30 of the trachea
6:33 or bronchi then as we begin to move down
6:35 into our lungs and we have our alveoli
6:38 these are little air sacs and the
6:40 surface area of the alveoli is about
6:42 that of a tennis court
6:44 which means there's a huge area for gas
6:46 exchange to occur and simply
6:49 what happens is the inspired oxygen will
6:51 jump into the bloodstream
6:52 and the carbon dioxide in the
6:54 bloodstream will jump out
6:56 into the alveoli and move in the
6:58 opposite direction and we will
7:00 expire so these are the various parts of
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