welcome to this pre-lab video for lab 10 covering the respiratory system in this laboratory we'll look at the overall organization of the respiratory system as well as look at the anatomy and histology of this amazing system the respiratory system can be broken up into two tracts pretty simply the upper respiratory tract and the lower respiratory tract we'll look at that in a moment physiologically or functionally the respiratory system can be divided up into two sections as well the conducting Zone and the respiratory zone so the conducting zone is really the straw it is the pathway by which air travels into the body through the nose and the nasal cavity down the ferin the larynx down the trachea progressively into smaller and smaller Airways called the bronchial tree this is going to go from larger structures called Brony plur bronchus down into smaller Airways called bronchioles once the air gets through the smaller bronchioles it'll now go into the respiratory portion and this is the portion the microscopic portion of the respiratory system where gas exchange is going to occur here there will be small Pockets uh little air sacks called alvioli we've been hearing about those alvioli now for weeks and uh recall that those alvioli are composed of simple squamous epithelia that allow for that gas exchange to occur so again if we just take a look at the anatomical division it's very very simple the upper respiratory TR versus the lower respiratory tract the way I remember this is that the lower respiratory tract includes the larynx okay LL so the lower the lower respiratory tract includes the larynx and everything inferior to that the upper respiratory tract includes the sinuses we'll take a look at these sinuses as we go through so if you have a sinus infection that's an upper respiratory infection if you have fitis or nasal infection those are also considered you uh Ur uh upper respiratory tract infections if you have laryngitis or bronchitis or pneumonia then you would have a infection of the lower respiratory tract so I think we're familiar that the major function of the respiratory system is to bring in air and exchange gases we think of this as a as a cycle a two-phase cycle there's inhalation and exhalation you might also instead call them inspiration and expiration inhalation draws the air and the gases into the lungs exhalation is going to force them out along the way though in addition to just exchanging gases there's a few other things that are going on as air comes into the respiratory system that air is going to be warmed it's going to approach body temperature it is going to be humidified moisture will be added to that air it will also be cleansed as it passes through the nasal passages remember we have pseudostratified columnar epithelium with cyia and mucus production occurring along this pathway as that air passes through the larynx we get voice production the molecules that are in the air are going to hit those olfactory receptors in the nasal passages and be picked up by cranial nerve number one and of course we know that along the respiratory tract there are goblet cells producing the mucus that's going to help trap foreign particles pollen viruses bacteria Etc so just to say this all over again everything in the upper respiratory tract is part of the conducting system so all of those structures of the espir of the upper respiratory tract would be part of the conducting system of the respiratory system you're going to get a chance to label many of these structures you'll see images or models like this image let's point out a couple things here number one the sinuses these are also called the paranasal sinuses these paranasal sinuses are air filled spaces we can only see two of them in this particular mid sagittal view they're named after to the bone in which they are found so there's the frontal sinus in part of the frontal bone this space can become infected to have a sinus infection there's also the sphenoidal sinus and you recognize it as it's right close to the cellat TSA remember the Bony housing area for the pituitary gland and recall that was a bone marking of the sphenoid bone so that's the sphenoid sinus there are two other sinuses that you cannot see in this particular view we'll see them in a moment there are also at maxillary sinuses and ethmoidal sinuses as you enter as air enters into the nostrils air is entering into the vestibule that is the opening into the nasal passages the nasal cavity and here you will see three nasal Concha the Concha are basically shelf like or tube like uh structures that are going to separate passages for the air as the air passes between those Concha it's traveling in a meatus you know a meatus is a tube like passageway so there are three meatuses in part formed by these three cona in the very back of the nasal passages we saw these before they're the frenal tonsils you know them perhaps more evenly as the as the adenoids part of that lymphatic structure we see back here as well the opening of the auditory tube remember this is also called the ustation tube or the fingio tanic tube it travels up to the middle ear here here is the hard pallet and the soft pallet and the soft pallette hangs down in what is called the uula so the uula is if you open your mouth and say A you can see the uula hanging down on either side of the uula as we saw last week in the lymphatic information there are the Palatine tonsils typically wouldn't be really obvious but if they're inflamed if you have tonsilitis those Palatine tonsils would be larger inflamed there's three parts to the ferx there's a nasal fings that's pretty much everything superior to the uula the oral ferx the area directly behind the oral cavity and the lorango FX down in the larynx this cartilagenous structure is the epig glotus you saw it a little bit in the fetal pig dissection of the digestive system that epiglottis is very important in regulating if food or air is going to get down the right pathway so as you're eating the epiglottis is going to shift and prevent food from traveling down into the into the Airways and that's the way by which food can only go down the the esophagus today though our focus is taking a look at the airway and so air is going to travel into change colors here air is going to travel down into the larynx the larynx is going to be officially uh described as being the epig glotus and some other cartilaginous structures you'll be taking a look at the thyroid cartilage the largest of these pieces of cartilage as well as the CID cartilage and then below the larynx one finds the trachea so again there are sinuses these are airfill chambers a moment ago you were only able to see two of them they are paired so you were able to see a moment ago the frontal and the sphenoidal I told you there's also ethmoidal and maxillary sinuses we'll take a look at those these sinuses are going to be lined by the same pseudostratified columnar epithelium that you see within the nasal passages and down the trachea they do in fact decrease the weight of the bones but they also give our voice their resonance qualities these ducts are connected by uh these these sinuses are connected by Ducks so infection can travel from one to another here's a diagram of those sinuses and you can see in fact the duct work between them again we cannot see the maxillary or the ethmoidal sinuses in our models because they're simply too lateral to that mid sagittal cut continuing our journey through the respiratory system into the ferx again this is a common pathway for both air and food we know it more commonly as the throat it is funnel shaped it is going to become more uh narrow as it travels inferiorly it's going to originate in the nasal regions pass through the oral cavity and go down to where the larynx and the esophagus um will bifurcate with the trachea the walls of the fering are rather flexible uh this is going to be for the purposes of swallowing we know there has to be some distension of that and already mentioned these three regions but there's the nasal fairings the oral fairings and Ling fairings let's take a look at those in an image so again from the posterior region of the nasal passages you have the nasal fings it's going to go to where the uula ends bottom of the uula then there's the oral ferx behind the oral cavity here's the tongue oral cavity straight back is the oral FX and then where the epig would shift down and from that point down you have the lingo fing again the lingo FX is uh going to be the area where you see the splitting of the esophagus and the trachea so now we are in the lower respiratory tract as we continue this journey now the lower respiratory tract has both parts of the conducting Airways and part of the respiratory portion so the conducting Airways of the lower respiratory tract would be the larynx the trachea the Brony and those bronchioles again those pathways through which air passes but there's no gas exchange and then the respiratory portion will be the microscopic regions where there is actually gas exchange happening this will start again in the respiratory bronchials go through some Alvar ducts and the alvioli in all of these words you see the word respiratory as in respiratory portion or you see some reference to the alvioli or the Alvar Ducks so the larynx you know it probably more as the voice box this is a pathway through which air can pass and sound is going to be produced as it passes by the vocal Folds there are nine pieces of cartilage uh three of them are paired so six pieces of the cartilage here and three individual pieces they're all held together by ligaments and muscles and this blingle uh cartilaginous structure will again house the vocal cords and allow for vocalization taking a look at the luring Gill struct structures again the larynx is includes the epig glotus and we've seen the epig glotus in the fetal pig it's that flap like structure here's the hyoid bone we haven't seen too much of the hyoid bone but there's that hyoid bone and the highway bone is part of this structure trying to hold this all together the largest piece of cartilage is a single piece of cartilage called the thyroid cartilage it's rather significant okay and then the second largest piece is the cry covid cartilage then there are the SE Rings or the tracheal cartilage pieces below that in addition uh there's also the retinoid cartilage the corniculate cartilage and the uniform cartilage so the most famous of all structures within the larynx would be the vocal ligaments or the vocal folds these are the true vocal cords and as air passes by these vocal ligaments the ligaments are going to vibrate this is going to produce sound there are actually a couple of structures in here um there are also the superior ligaments uh more commonly called the vestibular ligaments and we've been seeing that word vestibular a lot this semester so vestibular refers to anything in the entrance way into so as air travels first into the larynx passes by these vestibular ligaments these entryway ligaments these are really just vestibular folds and they are actually nicknamed the fult vocal cords they have nothing to do with sound production but they do protect the true vocal folds found below let's take a look at just the cartilaginous structures so again the largest piece of cartilage is the thyroid cartilage the second largest is the cry covid cartilage and here we're seeing the vocal ligaments the vocal ligaments you see them on either side here when you are breathing as on the right the vocal folds are separated and air is passing but when you are speaking those vocal cords or vocal ligaments are going to come together like two guitar strings and as air passes by they are going to vibrate that vibration is going to produce the sound that we are accustomed to hearing there's a video in your lab folder that will allow you to see those vocal cords while one is singing so I hope you'll take a look at that continuing the trachea is a flexible semisolid tubular structure you know perhaps as the windpipe it extends through the media steum and then is is going to be uh just in front of anterior to the esophagus it is the connect door between the larynx and the primary Brony depending upon how tall you are you have approximately 15 to 20 of these c-shaped terial cartilages they don't go all the way around as you will see in your fetal pig dissections and there is a muscle uh that connects the C Rings called the trachealis muscle take a look at this here so here is that c ring of cartilage here it's colored yellow so I'm going to highlight the yellow even more so so here is the cing right the cartilaginous c ring it's traveling around the trachea can't tell that higher magnification You' be able to see that that's Highland cartilage if we could zoom in you would see that this is pseudo stratified ciliated columnar epithelium you know what that looks like this is the airway or the Lumen of the trachea directly behind posterior to the trachea is the esophagus and so here's the esophagus you know that that would be a combination of skeletal muscle and smooth muscle depending upon where in esophagus you are more Superior it a skeletal muscle as one travels down the esophagus it becomes more smooth muscle and you also know that lining the inside of that esophagus would be stratified squamous non- caroen epithelium the muscle that I mentioned that is connecting the back side of those C Rings is the trachealis muscle and that's shown here here's the lingle structures the thyroid and the CID cartilage here are those SE rings and as air travels down the trachea it's going to come to a dividing spot the dividing spot's called the Corina where it splits from there air is going to travel into the left primary Bron heading to the left lung and the right primary broncus heading to the right lung notice that there's a difference there's an asymmetry here the left lung making room for the heart is going to have more of a lateral shift in the primary bronchus the right primary bronchus notice is much more per uh parall or straight down from the trachea histologically what is this going to look like some things here that you should easily recognize so we're zoomed in this is the Lumen of the trachea this is the pseudo stratifi colar epithelium that you're accustomed to seeing there' be cyia here on the surface there will be goblet cells with throughout this tissue making mucus and then there would be the Highland cartilage that you know to recognize with the condra sites once the air goes down the tracha you're now in the bronchial tree this is a continuous branching series of tubes through which air is going to pass there's a significant difference between Brony and bronchioles that I want you to appreciate as long as there is cartilage either partially or even a patch work of cartilage around an airway it is still considered a broncus and so as you go through the bronchial tree and they get smaller and smaller eventually you get down to bronchioles but as long as there's any sort of complete or incomplete incomplete ring of Highland carage it is still a broncus as I showed you a moment ago the right primary bronchus it's a little bit shorter it's wider it's more vertically oriented than the left side and that means that as foreign particles enter into the trachea they're more likely to go down into the RO right side because of its larger size and its orientation the Brony are going to enter into the hilum of each lung we'll see hilum uh in a number of organs and highum is simply where a majority of structures go into or out of an organ so you'll see that the pulmonary artery the pulmonary veins are going to come and enter and leave the lungs in a relatively small area lymphatic vessels will also go in and out as well as nerves in and out of the lungs in this area called the hilum the primary bronchus on each side will split into the secondary Brony these are often times called the lowbar Brony because they are heading there's a secondary bronchus for each lobe of the lung the left lung has two loes and so therefore there are two secondary brony whereas the right lung has three loes and so there are three secondary Brony the secondary Brony will then lead a smaller Brony called the tertiary Brony and that's as far as I'll expect you to be able to label these Brony so primary secondary and tertiary please do make note of singular versus plural so one bronchus and two brony so taking a look at this then we see here this would be the cardiac knot this is going to be making room for the heart for that reason the left lung has only two loes a superior and an inferior lobe whereas in the right lung again you see that there a larger primary broncus splitting into one two and three secondary Brony again this is a it's difficult to label these if you look up in the inset you'll see that there's a different color that really helps you to identify primary secondary and tertiary Brony but in this right side you can see that there are three loes there are two deep divide in structures so this a superior a middle and an inferior lobe so once the air has traveled through all of the conducting Zone it will get down into the respiratory zone of the respiratory system here there are small sacks called alvioli each lvi is a quarter to a half of a millim in diameter very very small this allows for a diffusion of the gases you have about 300 to 400 million of these alvioli between your two lungs and if you could spread the surface area out if you could spread all these millions of Alvi out it would be the size of a Double's tennis court so imagine a large tennis court that's how much surface area you have for the purpose of gas exchange you have seen the pulmonary arteries in the cardiovascular lab you know that this is bringing Venus blood into the lungs and you see that this blood is coming down into these individual capillaries that go around each alviola so the artist has not put put them on every Alvis but they would be there so you begin to appreciate how it is that you have 100,000 miles of vessels and capillaries in your body you have 400 million of these alvioli each Alvis is surrounded by its own delicate capillary bed of vessels so you see that the blood is coming in Venus blood it is then leaving out the pulmonary veins as red oxygenated blood from each of these Alvar capillary beds histologically let's take a look so you know that an artery has a significant layer of muscle around it so we can see that here we have a nice layer of muscle around it and you know that arteries tend to maintain their shape here is a bronchus and I know it's a bronchus and not a bronchol because as it points out there's a little bit of cartilage here now I know that that's difficult to see in this particular magnification but because it's pointing it out uh and because it's saying this up here change colors but because this is cartilage and it does go all the way around but because there's a patch of cartilage helping to protect and keep this airway open it is a bron is a bronchus right it's a small bronchus not a bronchol here the artist or not the artist the labeling of this phology is showing that this is a bronchiole okay much smaller there's no cartilage going around it just smooth muscle and then what you are probably struck by is this series of small airx so I'm just putting them in blue but all of these are the Alvi and they would all be surrounded Again by simple squamous epithelium so I want you to recognize the alvioli a bronchol versus a bronchus versus the trachea that I showed you earlier when it comes to histology so overall the gross anatomy of the lungs we've already seen this and I've already mentioned this um there are the different loes the lungs you know are separated by the [Music] mediastinum there is an apex that would be the more Superior border and the base would sit essentially on the diaphragm each long has a conical shape that you recognize protected by the rib cage and there is the portion of the lungs that is in direct contact with the thoracic wall with would be called the costal surface the rib surface so as we take a look this nicely shows the fissures that separate the lung lobes so in the left lung there's just one fissure that's the oblique fissure now there's an oblique fissure in both lungs there's also an oblique fissure on the right side but the right side also has a horizontal fissure and you see why it's called that horizontal fissure so that helps to separate out the loes again the Apex is on the superior side and the base sitting here would be sitting essentially on the diaphragm muscle