Overview of the Respiratory System

Hi, I am Aurel Enriquez and this presentation contains our discussion on the respiratory system. The structures of the respiratory system are used to acquire oxygen and remove carbon dioxide in the blood. So, diba po, nabanggit na natin ito in our previous discussions. Now, oxygen is required to create adenosine triphosphate or yung form of energy na kailangan ng mga cells natin. Now, on the other hand, carbon dioxide or CO2, this is a byproduct of ATP production. So after pong makreate ng adenosine triphosphate, ang byproduct nito or ang waste material dito is yung carbon dioxide. And this must be removed from the blood. So excessive accumulation of carbon dioxide could lead to negative effects in the body. Listed here are the main structural components of the respiratory system. First, yung point of entry po nung hangin na hinihinga natin, this would enter the external nose. So the nose is basically a chamber for the air that we inhale. Next, pagpasok po nung hangin sa ilong, it would pass through the nasal cavity. In this area, we would have nose hairs that would clean the air. Since the nasal cavity is more in the inner part, this would also warm the air that we breathe in. And also, we have mucous membranes that produce small amounts of fluid in our nasal cavity. So this could also humidify the air that we just inhaled. For some people, they have a problem in their nasal cavity, which is why they need help from... humidifier okay but for normal healthy people with a perfectly healthy nasal cavity no we don't need external humidifiers so our nasal cavity could do that for us after that the air that was inhaled would travel to the pharynx so this is also known as the throat all right and the pharynx is also a common area where air can pass through and the food that we ingest. After the pharynx, air would travel further down into the larynx, which is also called the voice box. So, don't forget their common names. Again, the pharynx is the throat, and the larynx is the voice box. So, this is the segment of our respiratory tract that also contributes to our ability to speak. speak by generating our voice. So again, the two main functions of the larynx is for breathing and for voice production. Paglagpas po ng larynx, next is the trachea. The trachea is also known as the windpipe. Alright, again, wagahalimutan yung common names. Pharynx is the throat, larynx is the voice box, and the trachea is the windpipe. Of course, sa mga upcoming quizzes, practicals, and exams natin, ang isasagot pa rin po natin is yung mga scientific names nila, okay? Which is the pharynx, larynx, and trachea. Anyway, the trachea, again, this is otherwise known as the windpipe, alright? So, ayan, kadugtong po ng trachea is yung mga bronchus, alright? So, bronchus, kung isa lang, bronchi, if we're talking about the two of them. All right. So they actually branch from the trachea and then they connect directly to the lungs. Finally, inside of the lungs, there's kind of like a maze or network of tubes where air would pass through. So this network is composed of alveoli, commonly known as the air sacs. OK, so again, alveoli is otherwise referred to as air sacs. Plus there are. there are also capillaries within that area. Now if you remember from our past discussion, the capillaries are the places where gas exchange could happen plus being in an area where blood could circulate. So there could be or this could be the place where there would be an exchange between carbon dioxide and oxygen within our blood cells. Alright now in our discussion on the respiratory system. the main site kung saan gas exchange lang talaga yung pakinabang nila would be the alveoli. Alright? So ulitin natin, sa alveoli po, for the most part, puro pag-enter ng oxygen and pag-exit lang ng carbon dioxide yung ginagawa nila dito sa alveoli. Listed here are the segments of the respiratory system. Simula sa nose hanggang sa larynx, that's the upper respiratory tract. Again, from the nose to the larynx, that's the upper respiratory tract. Simula sa trachea hanggang sa mga alveoli, that's the lower respiratory tract. Ulitin natin, from the nose to the larynx, that's the upper respiratory tract. From the trachea... to the alveoli, that's the lower respiratory tract. The conducting zone are the places where only ventilation could happen. So sa conducting zone daw po, pagdaan lang po ng hangin yung nangyayari dito. Let's compare that to the respiratory zone. So sa respiratory zone naman po dito, gas exchange ang ginagawa nila. Alright, so ulitin po natin, conducting zone, passage of air. only. No gas exchange. Sa respiratory zone, mostly gas exchange. This slide right here shows us the general structures of the respiratory system. So of course, as we go through our discussion, iisa-isahin din po natin itong mga ito. Let's now go through some definition of terms. Ventilation is the movement of air in to and out of the lungs. Alright? So literal na pagdaloy lang po ng hangin. That is ventilation. External respiration is the exchange of oxygen and carbon dioxide between the air in the lungs and the blood. Alright? So let's compare that with internal respiration. Internal respiration, this is the exchange of oxygen and carbon dioxide between the blood and the tissues. So, kung sa external respiration po, yung air and yung lungs yung nagpapalitan ng carbon dioxide and oxygen, sa internal respiration po, yung blood and tissues naman po yung nagpapalitan ng oxygen and carbon dioxide. Listed here are the other functions of the respiratory system. Ano pang ibang kayang gawin? ng respiratory system aside from exchanging oxygen and carbon dioxide. The respiratory system can maintain the pH of the blood by getting rid of the excess carbon dioxide. So first question, ano ba ang normal pH ng blood? Alright, so it's at 7.35 to 7.45, which is slightly alkaline. Ngayon, ano naman po? kung tataas yung carbon dioxide in the blood. Now, this could result in hypercapnia or respiratory acidosis. Now, patients with hypercapnia can present with tachycardia, dyspnea, confusion, headaches, and dizziness. So, let's define some of those. Tachycardia is a heart rate that is faster than normal or more than 100 beats per second. per minute at rest okay so based on our um previous discussion on the cardiovascular system yep it's at 72 beats per minute only all right next dyspnea so dyspnea this is a sensation of running out of air and of not being able to breathe fast enough or deeply enough so In simpler terms, just to simplify that statement, nahihirapang huminga. There is difficulty breathing. So dyspnea, difficulty breathing. Next additional function of the respiratory system is the production of chemical mediators. So the lungs can produce the enzyme ACE or the angiotensin-converting enzyme. Angiotensin-converting enzyme. also has the capability to regulate blood pressure. Alright? So may enzyme din daw po na pinoproduce yung respiratory system natin na kayang maapektuhan or kontrolin yung cardiovascular system natin, specifically our blood pressure. Next is voice production thanks to the larynx. Alright? So again, ano po ang common name ng larynx? It's the voice box. Okay? So as air moves through the larynx, nasa larynx po kasi yung vocal cords. So the vocal cords are the muscular tissues that are folded in a V shape. So dun sa vocal cords, sound is created. Other functions of the respiratory system include olfaction or the ability to smell. So, as we inhale, scent particles are also brought in. So, kasama ng hangin. So, the sensory neurons that our nasal cavity would detect and send signals to the brain. So, ulitin po natin, pag-inhale natin, may kasama yun na mga scent particles or mga chemical stimuli. So that would reach the olfactory nerves on our nasal cavity and send those signals to our brain. Next is protection. So the respiratory system provides protection against some microorganisms by preventing them from entering the body and removing them from the respiratory surfaces. So that's the reason why nose hairs at the entrance of our nasal cavity are present all right para pag may na inhale po tayo no kung para pag inhale natin kung may mga dust particles or pollution kasama dun sa hangin merong mga infectious organisms no at least na filter muna sila no mga hair strands present at the nasal passage so if ever po may mga microscopic infectious organisms na nakalagpas sa nose hairs natin Ang next level naman po is the mucous membranes of the nasal cavity. So they're supposed to stick or to be trapped by the moisture or mucous in the nasal cavity. Tapos eventually, iahatching or isisingan na lang po yung mga particles na yun. Nabanggit na po natin ito kanina on the... previous slide, here are the components of the upper respiratory tract. The external nose, the nasal cavity, the pharynx, and the larynx. Let's go through all of those parts one by one, starting with the external nose. So the tip of the external nose is mainly composed of hyaline cartilage. Okay, let's repeat. The tip of the external nose is made of hyaline cartilage all right so which is why it's um quite soft and has flexibility all right so when we die it would also rot away along with our soft tissues all right so you miss moon bone pot and skull the makita puna thing that be beginning shape so no snuff and would start at the nose bridge and then after that it's just hyaline cartilage Next is the nasal cavity. So it extends from the naris or the nostrils to the troana or the entrance, yung papunta na sa pharynx. Yung taas naman po, this is called as the hard palate and yung cartilage dito sa gitna that divides the two holes of the nose is called the nasal septum. Next part of the nose are the paranasal sinuses. So the paranasal sinuses are the openings to the nasal cavity. And this is the place that is lined with mucus. So if you would remember from our previous discussion, these kinds of mucous membranes, they're considered as the first line of defense and is part of our innate and non-specific immunity. Next is the concave. So the concave, these are the bony projections on each side of the nasal cavity. So sa loob daw po ng nasal cavity, meron parang pader kung saan may mga nakaprotrude na mga bones. Alright, so these protrusions would increase the surface area of the nasal cavity. The greater the surface area means that the air from the outside would have more places or areas in our nasal cavity to make contact with. which would help it in warming up the air from the outside. Last part of the nose is the nasolacrimal ducts, also known as tear ducts. So ito daw po yung daanan ng luha and connected din daw po ito sa nasal cavity. Again, that is referred to as the nasolacrimal ducts. Listed here are the functions of the nasal cavity. This would remain open even when the mouth is full of food. Okay, so dalawa po yung pwedeng daanan ng hangin na hinihinga natin, the nose and the mouth. But breathing through the mouth is not really a good practice. Okay, pero ayan niya po in cases of people who are mouth breathers, at least even when their mouth is filled with food. food, the air can still pass through. Next, the nasal cavity could clean the air that we breathe in. This is because of the hairs which would trap large dust particles and the mucous secretions that could catch the smaller particles. Third function is to humidify and warm the air, which again is a function of the conque. Our nasal cavity is also the area where our olfactory epithelium is located, which again is very important to be able to smell. Next, it helps determine how our voice would sound. So the nasal cavity and the paranasal sinuses are the resonating chambers for speech. So basically, our voice sounds like this because of the way that the air has passed through our nasal cavity. nasal cavity and paranasal sinuses which is why when we have a sore throat, for example, we have a sore throat, the sound of our voice changes. So again, that's one of the reasons because it's part of the function of the nasal cavity. Again, the nasal cavity and paranasal sinuses determine the sound of our voice. So again, when we are sick or if for example our nasal passages or nasal cavity is blocked, all right this could affect the sound of our voice let's now talk about the next segment of our upper respiratory tract which is the pharynx all right so again the pharynx is otherwise referred to as the throat and this is the common passageway for the respiratory and digestive systems all right so again pharynx can go through both air and food so the pharynx is actually divided into to three segments or three areas. First up is the nasopharynx. So as the name implies, ang katapat nito is the nasal cavity. So this would take in the air that we inhale. Next is the oropharynx. As you would expect, ang katapat po nito is yung oral cavity. So this extends from the uvula to the epiglottis. Next is the laryngopharynx. So the laryngopharynx the laryngopharynx would extend from the epiglottis up to the esophagus. Next, what is the uvula? The uvula is otherwise referred to as a little grave, which is the extension of the soft palate. So, this is the most well-known structure that we usually refer to as the tonsil. But if you would remember our discussion on the lymphatic system, there are three different types of tonsils. Now, for our discussion on the respiratory system, we will only be mentioning the pharyngeal tonsil. So within the pharyngeal tonsil, we can see the structure of the uvula. So the pharyngeal tonsil... Now this aids in defending against infections, which again we've already mentioned that when we discuss the lymphatic system. This illustration right here shows us all the specific structures that we may be able to find within our nasal cavity and our pharynx. So dito pa lang po, nasal cavity and pharynx pa lang, napakarami ng mga specific parts na kailangang aralin. The third component of the upper respiratory tract is the larynx. Again, this is otherwise referred to as the voice box. So this is located in the anterior throat that extends from the base of the tongue to the trachea. So let's repeat the area where the larynx is. It starts at the base or below the tongue until the trachea. So the larynx consists of nine cartilages. So, ayun po. we have what is known as the thyroid cartilage. So the thyroid cartilage, this is the largest piece of cartilage that is attached to the larynx. And this is referred to as the Adam's apple. So in males, this is referred to as the Adam's apple. Now in females, the thyroid cartilage is not that prominent, so it doesn't have a specific name for females. Let's just clarify this, alright? Lahat ng tao Regardless whether you are a male or female, lahat po ng tao, everybody has a thyroid cartilage. Okay? So again, everybody, regardless of gender or biological sex, no? Everybody has a thyroid cartilage. It's just that it is a bit more prominent in males. So yun po yung na-observe natin na Adam's apple. Alright? So wala tayong nakikita na Adam's apple in females because their thyroid cartilage. is not that prominent or not that large, all right? But it is there. It is present, all right? Females also have a thyroid cartilage, but it is not as protruding or as prominent as that of males. So again, the Adam's apple is another term, just another term for the thyroid cartilage. Another part of the larynx is the epiglottis. So this is a... piece of cartilage that looks like a flap, alright? So this flap would prevent swallowed materials from entering the larynx, okay? So let's repeat, the first part before it reaches the larynx is the pharynx, right? And the pharynx is the common area where both air and food items could pass through, right? So there, again, the advantage of epiglottis is to flap and cover, right? To cover the larynx so that food particles will not accidentally pass through the larynx, which the next segment is trachea. So again, the epiglottis serves as some form of covering to prevent the entrance of food items that came from the pharynx. This slide right here shows us all the other specific parts and the other types of cartilage that would make up the larynx next next are the vestibular folds so the vestibular folds these are just false vocal cords next are the vocal folds so the vocal folds these are the actual sources of voice production all right so need to put a vocal folds when air moves pass them, so kapag dumaan daw po sa vocal folds yung hangin, they would vibrate, and then sound is produced. Okay? So again, sound is being produced through the vibration of our vocal folds. They vibrate as air passes through. So, the force of the air determines the loudness of our voice. Alright? Yung puwersa daw po ng hangin, this would help us adjust kung gano kalakas or kung gano kahina yung boses natin. Now the tension that we produce on our throat, the tension would determine the pitch of our voice or kung gaano katinis or kung gaano kalalim yung boses natin. This slide right here shows us a visual representation kung saan po located yung larynx natin, which again is right here, simula sa base of the tongue. Next, here is an illustration of all these structures. that we've talked about earlier and right here is an actual photo of our larynx through superior view. Let's now go through the parts of the lower respiratory tract starting with the trachea and then the bronchi, tracheobronchial tree in the lungs, and then the alveoli. Again this illustration right here just visually shows us where our upper And lower respiratory tract would be located and kung ano po yung mga components nila. Again, the upper respiratory tract is composed of the nasal cavity, pharynx, larynx, and syempre kasama dito yung entrance which is the external nose. Next, the components of the lower respiratory tract would be the trachea, bronchi, and the lungs. And of course, yung mga alveoli na nandito po sa looban ng lungs. First structure at the lower respiratory tract is the trachea, commonly known as the windpipe. So this is made up of 16 to 20 letter C-shaped rings of cartilage, and those rings are called tracheal rings. So let's repeat, these 20 letter C-shaped cartilage are called tracheal rings. So if we arrange them together, this will create the trachea. Given here are other facts about the trachea. So this is lined with pseudostratified columnar epithelium. Again, if you would rewind to our discussion on tissues and histology, kapag sinabi po natin na pseudostratified columnar, they only look like they are stratified or they falsely look like they are multiple layers. Pero hindi po talaga. They're just varying in... They're varying in... in sizes, and also the locations of their nucleus. So, it's like their appearance is not even, that's why they're called stratified. But in general, they are columnar, meaning they are cells that are taller in comparison to their width. So, let's repeat, the trachea is lined with cells that are referred to as pseudostratified columnar epithelium. Now the problem here is that smoking could kill the cilia. So basically, in Tagalog, pinuponpon or sinisira daw po ng habit of smoking yung hair-like structures sa ibabaw ng pseudostratified ciliated colunar epithelium. Next, coughing dislodges materials from the trachea. So kung halimbawa naman po may foreign materials, foreign particles, or irritated particles. that passed through our windpipe. Then what would happen is the natural reaction of our respiratory system would be to eliminate those or to get rid of those through coughing. This illustration right here shows us the anatomy of the trachea and the lungs. Alright, so again there are different parts right here that has been labeled. What we see here are white spots. Dito, ito po yung mga cartilage or yung mga C-shaped cartilage that would create the trachea. Now, as you can see right here, the air passageway would decrease in size. Notice, no, na in terms of the diameter, no, visually, mas malaki talaga yung daanan ng hangin simula dito sa larynx hanggang sa trachea. But they decrease in size but increase in number as we go. go to the inside of the lungs. So as we can see right here, the passageways will become smaller and smaller, but the branches would continue to divide. So again, don't forget to study the parts and labels that we see here. Next stop is the bronchi. This is basically an extension of the trachea because it's also... made up of the same letter C-shaped cartilage, but it branches into the left and right bronchi that would directly connect to the left and right lungs. So just like trachea, this is also lined with cells that have cilia. This slide right here just lists down the components of the tracheobronchial tree. So we mentioned earlier, right? structures would become smaller and more numerous from the primary bronchi to the alveoli. So, from the larynx to the trachea, the passageway for the air is a bit wider. As we move to the inside of the lungs, the passageway gets smaller, but at the same time, there are more branches. Alright, so first up we have the primary bronchi. So, this would be further divided into the... lobar or secondary bronchi, the segmental or tertiary bronchi, until eventually it branches off into the tinier bronchioles, all right? After that, we have the terminal bronchioles and then the respiratory bronchioles. So, tuloy-tuloy lang po. Branch lang ng branch hanggang umabot sa alveolar ducts and the alveoli, okay? So, pagdating po sa alveoli, This is again not otherwise referred to as the air sacs where exchange of gas or gas exchange would actually happen. This slide talks about changes in air passageway diameter. Bronchodilation happens when the smooth muscles around our bronchioles relax, allowing our airways to be larger in diameter. So basically, mas maluwag po yung daanan ng hangin. Bronchoconstriction happens when the smooth muscles around our bronchioles contract, making bronchial diameter smaller. Dito naman daw po sa bronchodilation, imbis na relax, nagkokontract daw po yung smooth muscles sa paligid ng mga bronchioles. So sumisikip din daw po yung daanan ng hangin. Next, what happens during asthma attacks? This is the contraction of the terminal bronchioles, resulting in reduced airflow. So basically, the bronchoconstriction also affects the people who are breathing, so they have a hard time breathing. Let's now talk about the alveoli. So the alveoli are the sites for external respiration. All right. So the alveoli are otherwise referred to as our air sacs. All right. So small air filled sacs where air and blood would come into close contact. And this is where gas exchange would happen. All right. So our alveoli, they're actually surrounded by capillaries. According to this slide, simula daw po sa terminal bronchioles natin, there are multiple levels of branching. Alright, so this is something that we've always mentioned simula kanina, di ba? Na simula sa larynx and trachea, there is a wide diameter of passageway for the air. Pero as we move through, lumiliit yung mga daanan ng hangin, but at the same time, there's continuous branching. So ganun din po dito, there are multiple levels of branching. Especially when we start or when we come from the terminal bronchioles. So first up, we have what is known as the respiratory bronchioles. So they have a few alveoli. Alright, so a few alveoli are attached to them. Next, we have the alveolar ducts. So they arise from the respiratory bronchioles and open into an alveoli. So let's repeat. Starting from the terminal bronchioles. may respiratory bronchioles. Simula sa respiratory bronchioles, meron ng konting mga alveoli. Pero, if we like further go through the branches, simula dito sa respiratory bronchioles, magpa-further divide pa ito into alveolar ducts. So, dito po nag-open up na siya into other alveoli. Next are the alveolar sacs. So, these are the chambers connected to two or more alveoli. at the end. Alright, so sa alveolar sacs po dito, ayan niya, medyo mas marami na tayo makikita ng mga alveoli dito. So we would understand this better as we look through the illustration on the next slide. This slide shows us all the structures that we've discussed in the previous slide. So again, if for example, this is our terminal bronchiole, this would further divide into the respiratory bronchioles or these three segments or divisions right here. So itong mga respiratory bronchioles, it has been described that they have a few alveoli attached to them. So may mga pa-isa-isa na tayo makikita dito. So as you can see right here in this label, right here we're seeing one alveolus. Okay, so kapag isa niya lang alveolus, kapag madami sila, alveoli. Okay. Next, the respiratory bronchioles with further branch into the alveolar ducts. So, pagdating sa alveolar ducts, tuloy-tuloy na siya hanggang sa alveolar sacs. Alright, so dito sa alveolar sacs, definitely, mas marami na tayong ma-observe na alveoli as we can see right here in this illustration. And of course, the alveoli are also surrounded with a network of capillaries. capillaries, as we can see right here in this illustration. So these ones right here are labeled as the pulmonary capillaries. Let's now talk about the respiratory membrane. So the respiratory membrane is found in the lungs, and this is where gas exchange between the air, yung hangin, nakakainhale lang natin, and the blood would occur, right? So the respiratory membrane is formed by walls of alveoli and capillaries. So, yun nakita po natin dun sa previous illustration kung saan may mga alveoli na nababalutan ng mga capillaries. So, yun po, we would refer to that area as the respiratory membrane. So, alveolar ducts and respiratory bronchioles would also contribute to these activities of exchanging gases. So, ayun po. The respiratory membrane is observed to be very thin for the easy diffusion of gases, which makes sense. It needs a single layer of cells to pass through the gases so that they can easily pass through from one area to another. So for example, the oxygen needs to be able to diffuse or move from the alveoli to the other. sa blood circulation. And the other way around, kung may carbon dioxide po na nandoon sa blood circulation, dapat madali lang din para sa kanya to exit the capillaries and move into the alveoli in preparation for exhalation. So again, it makes sense that they are very thin for the easy diffusion of gases. Listed here are the layers of the respiratory membrane. So again, let's focus on the specific layers with highlights. First is the alveolar epithelium. The alveolar epithelium is made up of simple squamous epithelium, which again is only composed of a single layer of cells. Next, it has a thin interstitial space. And next, it has a basement membrane of capillary endothelium. This is also made up of simple squamous epithelium. So again, like what we mentioned in the previous slides, you really need a single layer of cells for the passage of gases for easy diffusion. This illustration right here shows us the alveolus and the respiratory membrane. So if, for example, the airspace within our... alveolus. Ito yung mga areas kung nasaan pwede tayong makakita ng mga capillaries or kung saan pwedeng dumadaan yung mga RBCs. Now, if we were to zoom in further in this area, makikita natin na kung halimbawa ito yung airspace ng alveolus, ito naman po yung respiratory membrane or yung area kung saan mahanap natin yung blood circulation. So again, there's only a simple example. squamous epithelium between these two structures. So again, they should be simply layered so that the diffusion of oxygen can be easily diffused to the RBCs and the diffusion of carbon dioxide from here to the alveolus. So when the carbon dioxide goes to the alveolus airspace, it's ready to be exhaled. All right. So again, if you belong to my laboratory classes, huwag pong kakalimutan na aralin itong mga parts that have been labeled right here. Let's now look at the anatomy of the thoracic wall. It's composed of multiple structures like the thoracic vertebrae, the ribs, the coastal cartilages, the sternum, and all the muscles that are attached to these areas na tumutulong para makapag-move yung thoracic wall whenever we breathe in or we breathe out. Alright, so of course, since our lungs expand and contract when we inhale and exhale, it's important that there are associated muscles here to help with that expansion and contraction of our lungs. The thoracic cavity is a space enclosed by the thoracic wall and diaphragm. So, all the structures structures that we enumerated earlier plus the diaphragm underneath that, this would create the space that is referred to as the thoracic cavity. So we discussed this when we talked about the muscular system. The diaphragm is a skeletal muscle involved in normal quiet breathing. Let's now talk about the lungs. So the lungs is the primary organ of respiration. Alright? So marami tayong na-discuss kanina, diba, ng mga ibat-ibang parts, ibat-ibang segments that would create our upper and lower respiratory tract, right? But the main organ that is responsible for our breathing is the lungs. Another description said here is that it is cone-shaped, alright? So medyo pointed yung itaas, tapos mas malapad yung ibaba. Alright, so again, the lungs is somewhat... cone shape. Next, the base rests on the diaphragm. Alright? So yung base daw po, ito yung area that is within contact on top of the diaphragm. Alright? And the apex extends above the clavicle. So yung apex or yung slightly pointed part daw po nung lungs natin. So nag-extend daw siya. Medyo mas mataas ng kaunti sa clavicle natin or dun sa collarbone. Our clavicle is otherwise referred to as the collarbone. So the right lung has three lobes. So it seems like there are three more segments of the right lung. Meanwhile, the left lung only has two lobes. So on the next photo, we will see that. These illustrations right here shows us the lungs, their lobes, and the bronchi. all right so this one is the right lung and this one is the left lung all right so right here on top The one that is seen to be a little bit pointed, that is the superior lobe. Then let's move to the right. So on the right, it has three lobes. So if this is the superior lobe, right here it has what is known as the horizontal fissure, dividing the middle lobe. So the middle or the second lobe is right here. Next, it has what is known as the oblique fissure. And then, this would show us that it is here on this side, the inferior lobe or the lobe that is below or closer to the base. Okay? So, there. Again, superior lobe, middle lobe, and inferior lobe. These are the components of our right lung. In comparison to the left lung, the left lung only has two lobes. Alright? It doesn't have a middle. Okay? It's just the superior. and the inferior lobe. Alright? And as we can see right here, we have areas that are referred to as the cardiac impression, cardiac notch. Alright? So, ito po yung areas, most likely, kung saan nakaharap yung apex nung heart natin. Diba? If you would remember our discussion on the heart, diba po? The heart is located in the middle of our two lungs. Pero yung apex po nung heart, no? The apex of the heart is facing towards the left lung. Alright? Kaya po, mas na, mas na dedetect natin yung heartbeats ng isang pasyente by checking the left side of their chest. And ayun nga po, there are cardiac impressions and cardiac notches on the left lung to make space or to make way for the apex of the heart. Alright? So again, this is the structure of the right lung and left lung. Let's now talk about blood flow to the lungs. So oxygenated blood has passed through the lungs and picked up CO2. So again, definition of terms. Kapag sinabi natin na oxygenated na yung blood, oxygenated blood means that nakadaan na po siya sa lungs. So nakahingi na siya ng oxygen. On the other hand, kabaliktaran po nito is deoxygenated blood. So kapag sinabing deoxygenated na po yung blood supply, It has already gone through the tissues. So, dumaan na siya sa systemic circulation natin. Dumaan na siya sa lahat ng iba't-ibang tissues natin. And it has already released some of its oxygen content. So, basically, naipamigay na po niya yung oxygen na meron siya. So, it's now referred to as deoxygenated. Alright? So, ulitin natin. May oxygen pa, oxygenated. Wala ng oxygen, deoxygenated. Next. Pulmonary capillaries would carry the deoxygenated blood to the pulmonary arteries. Pulmonary arteries would carry the deoxygenated blood to the pulmonary capillaries. So again, huwag pong malilito. Yung pulmonary arteries, sila yung magdadala ng deoxygenated blood papunta sa pulmonary capillaries. After that, the blood would become oxygenated and return to the heart through the pulmonary veins. Alright? So again, if you would remember one of the illustrations that we've seen earlier, right? The pulmonary capillaries. These are the capillaries that are right next to our alveoli. Alright? So, the respiratory membrane is here where gas exchange would happen. Right? So, that's what happens. Alright? So, if it's already delivered or if it's already entered the pulmonary gap. arteries, the deoxygenated blood, the blood that is already depleted from the pulmonary arteries, the oxygen supply, will reach the pulmonary capillaries. When it comes to the pulmonary capillaries, they will gas exchange, the blood will be given its carbon dioxide and then it will receive the oxygen. After that, the blood would now become oxygenated again and this would return to the heart by passing through the pulmonary veins. Let's now talk about the lymphatic supply to the lungs. Alright, so first up is the superficial lymphatic vessels. So this surrounds each lung. Alright, so basically, it's just surrounded by the lungs. Meanwhile, the deep lymphatic vessels would follow the bronchi. Alright, so may mga lymphatic vessels din po tayo. na sinusundan niya yung bronchi papasok doon sa lungs. Alright, so that's the difference between superficial and deep lymphatic vessels on the lungs. Let's now talk about plural membranes and plural cavities. Alright, so yung plural cavity po, this is the space around each lung. Alright, so again, ang keywords po natin dito, kapag sinabing cavity, this is a space. Alright, so yan po, tinawag siyang plural cavity because this is a space specifically around each of our lungs. Next is the pleura. So the pleura, this is a double-layered membrane. that surrounds the lungs so there are two types of pleura okay so first up is the parietal pleura so the parietal pleura this is the membrane that lines the thoracic cavity okay so ito po yung parietal pleura no naka attach siya dun sa thoracic cavity let's compare that to the visceral pleura the visceral pleura is a membrane that covers the lungs surface so yung visceral pleura Alright, this is directly attached to the lungs. Alright, so there. When we say parietal, the surroundings are what it holds or wraps. When we say visceral, the same organ wraps this membrane. So again, when we say parietal pleura, this would line the thoracic cavity. But when we say visceral pleura, this would cover the surface of the lungs. This is directly attached. on the surface of the lungs. This illustration right here shows us a superior view of our lungs. So if we were to look at this illustration right here, if we were to make this cut right here on top, what will happen is we will be able to visualize the lungs in this specific angle or in this specific view. So as we can see right here, Imagine that the person is facing you. So yung likod niya, nandito, alright? Andito yung vertebra. Yung harap niya, nandito. Kasi nandito yung sternum. Alright? So ayan po. Magtatandaan yung locations ng parietal pleura, pleural cavity, and yung visceral pleura. So yung parietal pleura, naka-attach siya or ang kinukover niya is yung lining ng thoracic cavity. Yung pleural cavity, yun yung space sa pagitan nila. This is the visceral pleura. This one is a membrane that is directly attached to the surface of the lungs. Let's now talk about the process of ventilation or simply breathing. So this is the process of moving air in and out of the lungs. So that's how simple it is. The air flowing as we inhale and the air flowing as we exhale. That's it. That's what we mean when we say ventilation. So there are two aspects of ventilation. This may be brought about by the action of the muscles of respiration. So yun nabanggit natin kanina na yung diaphragm and then the muscles within our thoracic cavity or thoracic wall. Next, air pressure gradients. So ito po yung dalawang factors that influence our ventilation or breathing. Listed here are the muscles of inspiration, otherwise referred to as inhalation. Alright, so ito daw po yung mga muscles na tumutulong sa atin na mag-inhale. Alright, so this increases the volume of the thoracic cavity. So listed here are all the muscles that would help us inhale. The diaphragm, external intercostals. pectoralis minor, and scalene muscles. Alright, so don't forget, enumerated here are all the muscles that would help us inhale. Let's now talk about the muscles of expiration or the muscles that would help us with exhalation. So these ones would decrease the thoracic volume by depressing the ribs and the sternum. Alright, so basically, these muscles are compressed. yung ribs and sternum natin kind of like giving a squeezing motion to our lungs to help us exhale all right so the internal intercostals the transverse thoraces and the abdominal muscles these are the three muscles that are involved in expiration or exhalation all right let's repeat the muscles that are involved in exhalation would include the internal intercostals transverse thoracis, and abdominal muscles. Let's now talk about quiet in comparison to labored breathing. So in quiet breathing, expiration or exhalation is a passive process. So when we say passive, we don't have to consciously think about it anymore. We just breathe normally without attempting to control our rhythmic breathing. So let's compare that to labored inspiration or labored expiration. All right. So in labored. inspiration, more air moves into the lungs because the inspiratory muscles are more active. Alright, so here, our muscles that are involved in inhalation work more, that's why more air enters our lungs. Next is labored expiration or labored exhalation. So with this one, more air would move out of the lungs because of the forceful contraction. of the internal intercostals and abdominal muscles. So, dito po, in-specify nila yung dalawang muscles that is involved in labored exhalation. Alright? So, again, mas maraming air yung lumalabas sa lungs natin because of the contraction of the internal intercostals and abdominal muscles. Inspiration or inhalation happens when the thoracic cavity volume increases. So basically, the space of the thoracic cavity expands. Another thing that happens during inhalation or inspiration is the atmospheric pressure is greater compared to alveolar pressure. So the atmospheric pressure is stronger, the force of the air entering our lungs is stronger. So air moves into the alveoli. So that's what happens during inspiration or inhalation. Next, expiration or exhalation happens when the diaphragm relaxes and the ribcage recoils. So what happens here is that the thoracic cavity volume decreases. The space of the thoracic cavity decreases. So the thing that we would be able to observe here is that the alveolar pressure is greater compared to atmospheric pressure. So the force of the air that comes out of our alveoli is higher compared to the air that comes in from the outside. So what would happen here is air would move out of the lungs. So again, that's what happens during expiration or exhalation. Alveolar ventilation is the measure of the volume of air that is available for gas exchange per minute. Now, we need to take note that there is an area within our lungs where no gas exchange would happen. And this is referred to as the dead space. Let's repeat it. There is an area or place in our lungs where no gas exchange happens. And that place is referred to as the dead space. Listed here are the different factors that affect our ventilation or breathing, right? So gender, age, body size, and physical fitness, right? So again, gender, age, body size, and physical fitness are the things that we could consider or factors that we need to consider that would affect our breathing, right? So emphasis on body size and physical fitness because these two are the most readily observable among the fact of... among these four factors that would affect our breathing. Lung recoil is the tendency for an expanded lung to decrease in size. So basically, pag sinabi pong lung recoil, kapag katapos nating mag-inhale, mag-expand yung lungs. But after nating mag-inhale, kailangan niyang bumalik to its original size. So the expanded lung would decrease in size. And this happens during quiet breathing. expiration or quiet exhalation right so long recoil is brought about by the elastic fibers and the thin film of fluid lining our alveoli so nagging possible in a book along recoil because of the elastic fibers and film of fluid in like that is lightning that is lightning our alveoli Next, what are surfactants? Surfactants is a mixture of lipoproteins, alright? Lipids and proteins. So this is produced by secretory cells of the alveoli, alright? So ano po ba ang mga surfactants? This is a fluid layer on the surface lining the alveoli, alright? So there's a small amount of fluid daw po sa mga alveoli natin and it reduces surface tension and keeps our lungs fluid. from collapsing all right notice our lungs is basically um a place that is filled with air sacks all right so na paka spaces that's just filled up with air so back at hindi ito basta basta nagko collapse or na na de de form nagi squish no um as time goes by or as we um kind of like strain our lungs all right so again This happens because of the presence of our surfactants. All right. So again, surfactants, they are made up of lipoproteins. They are produced by secretory cells of the alveoli, and they form a fluid layer that prevents the lungs from collapsing. Let's now talk about gas exchange in the lungs. So blood returning from the tissues and entering the alveoli in the lung has a lower partial pressure of oxygen. So let's repeat that statement. The blood from the tissues is deoxygenated. They don't have any more oxygen with them. So that means they have a lower... partial pressure of oxygen kasi nga halos wala na silang oxygen na dala and a higher partial pressure of carbon dioxide right so um oxygen diffuses from the alveoli all right so mula daw sa alveoli magde-diffuse or pupunta sa blood natin yung oxygen and then um kabalik na rin nito co2 diffuses from the capillaries okay so ili-let go nung blood cells natin yung carbon dioxide na meron sila, and ipamimigay nila ito papunta sa alveoli para may exhale na natin. That was for the gas exchange in the lungs. Let's now talk about gas exchange in the tissues. So blood traveling from the lungs, okay? So yung blood nanggaling na daw sa lungs. So nakahingina sila ng oxygen. Diba po? They have a higher partial pressure of oxygen. Alright, so mas mataas daw yung partial pressure of oxygen nila kasi nga po, diba, may bit-bit na sila or may daladala na silang oxygen molecules and they have a lower partial pressure of carbon dioxide kasi diba, what happened earlier in the lungs? Pinamigay na nila dun sa alveoli yung carbon dioxide that they were previously carrying. Okay, so oxygen diffuses from the capillaries into the interstitial fluid. When there is gas exchange in the tissues, pagdating po sa mga specific tissues ng blood flow natin, ipamimigay na niya or ididefuse na niya yung oxygen galing sa capillaries and mapupunta na ito sa interstitial fluid. On the other hand, CO2 diffuses from the interstitial fluid into the blood in the capillaries. So, ang mangyayari, yung mga... carbon dioxide produced by our cells and tissues they will exchange it to the blood present in our capillaries to deliver it back to our lungs to exhale the carbon dioxide from our lungs let's now talk about respiratory membrane thickness so increased thickness decreases rate of diffusion. Alright? So, one thing that we've already mentioned earlier, is the structure of our alveoli and capillaries. Alright? Or yung respiratory membrane. So, both of them, they have simple endothelium. Simple squamous endothelium. So, manipis na layer lang po ng cells para easy yung diffusion ng gases. Now, what happens here is that if... For example, a person is experiencing pulmonary edema, meaning there is accumulation of fluid in the lungs. This would decrease diffusion. So, the diffusion of gases is a bit slow if a person has pulmonary edema. So, the rate of gas exchange is decreased. So, oxygen exchange is affected before carbon dioxide because carbon dioxide diffuses more easily than oxygen. So kapag may pulmonary edema daw po ang isang pasyente, mas nagiging apektado or mas nauunang bumagal yung pag-diffuse ng oxygen kasi medyo mas mabilis daw pong i-diffuse or i-release ang carbon dioxide compared to oxygen. Let's now talk about hemoglobin. Now if you've already watched our discussion on the human blood, Review na lang po ito sa atin. Diba? So hemoglobin, this is a protein that occupies about one-third of the total volume of the cytoplasm of red blood cells or RBCs. Alright? So again, if you would remember the structure of RBCs, they are a biconcave disc with no nucleus. Diba? So hindi na po kailangan ng mga RBCs ng nucleus. Alright? So that entire area is now filled up. with hemoglobin. So hemoglobin. consists of four units, each containing one iron-based heme group which binds to oxygen. Okay? So, ulitin natin, o, or reviewin natin kung aning structure ng hemoglobin. It is composed of four globin molecules. Diba? Tapos, sa bawat globin molecule, may naka-attach na heme. Sa bawat heme molecule, meron naka-attach na iron. Alright? And dun sa iron molecule, dun... mag-attach yung oxygen. Doon magbabind yung oxygen para mabit-bit ito ng red blood cells. So, ayan po. Let's now talk about the regulation of ventilation or regulation of breathing. The respiratory rate or breathing rate is regulated to maintain gas concentrations. So, hindi daw po mabuti. na sobra yung pag-inhale natin, di rin naman mabuti na sobra yung pag-exhale natin. So, of course, our breathing needs to be regulated. So, there are neurons in our medulla oblongata that control the rate of ventilation through stimulation of the muscles of respiration. Alright, so ulitin po natin yung part na yun sa medulla oblongata natin. At our brain, there are neurons within our medulla oblongata. where they control the muscles of respiration. So they control the muscles that are involved in inhalation and the muscles that are involved in exhalation. So again, this happens in the medulla oblongata. Let's talk more about that medullary respiratory center. So again, the medullary respiratory center is located at our medulla oblongata. And it has two components, right? The dorsal respiratory group or DRG and the ventral respiratory group or VRG. Okay? So yung dorsal respiratory group na po, this is most active during inspiration. Okay? So mostly kapag nag-i-inhale tayo, ang nagtatrabaho po dito is yung dorsal respiratory group. Meanwhile, yung ventral respiratory group na po, this is active during inspiration. inspiration and expiration. So both for inhaling and exhaling, what it works for is the ventral respiratory group. Another thing about the ventral respiratory group is that it contains the pre-Bertzinger complex, which is believed to establish the basic rhythm of respiration. constant rhythm of our inhale exhale, pre-Botzinger complex was established. What is the pre-Botzinger complex anyway? The pre-Botzinger complex or pre-Botz C is a neural network that is responsible for inspiration during respiratory activity. This is the part of the V.R.G. that is involved in inspiration or inhalation. is ito sa mga bagay na um kumbaga is parang may control yung pre-BOTC all right so in 1991 medyo recent pa po ito no in 1991 the pre-BOTC was described as a region of the ventral medulla of longata containing the neural pathway that is necessary to generate respiratory rhythm all right so ulitin po natin yan kung na-confuse kayo sa statement na yun nung 1991 no they discovered the pre-Botzinger complex. So this is the part in the ventral area of the middle of the lung. They have been able to find out that this is the part of our brain that is responsible for creating our respiratory rhythm. Or the rhythmic inhale-exhale. This slide right here shows us the location of our medullary respiratory center, which is right here. And then, it teaches us where the specific muscles or specific areas that are influencing our medullary respiratory center to help us with inhalation and exhalation. Let's now talk about the generation of rhythmic ventilation. Alright, so how does the rhythm of breathing in and breathing out create? First up, we would have the starting inspiration. So the medullary respiratory center establishes the basic rhythm of ventilation. Alright, so this would receive stimulation from the receptors for blood gas levels. So for example, Is the oxygen level too high? Carbon dioxide levels? Those types of things. Another thing that they would be considering is blood temperature. Next is the movements of our muscles and joints. So of course, the movements of our muscles and joints would require energy. And energy would be created with the help of the oxygen supply. Again, movements of muscles and joints that would also affect our starting inspiration. And of course, emotions. There are people out there that when they're experiencing certain emotions, their breathing also changes. Example, kapag ginakabahan yung isang tao, lumalalim yung paghinga nila. Another thing would be if a person is experiencing... a panic attack now for some people experiencing a panic attack maari po na bumilis naman yung breathing rate nila so ayun po emotions could also affect our starting inspiration now input from receptors causes action potentials that stimulate the respiratory muscles so basically kapag itong mga factors na to blood gas levels movement emotions kapag ito po ay naprocess na medullary respiratory center, it will start sending action potentials to our respiratory muscles. Second step is the increasing inspiration. Once inspiration begins, more and more neurons are activated. So when our inhale starts, basically, it will encourage other neurons to work. medullary respiratory center to progressively create a stronger stimulation of the respiratory muscles. Third one is the stopping inspiration. So neurons stimulating the muscles of respiration could also stimulate neurons that are responsible for stopping inspiration. So again, they're attempting to achieve some form of homeostasis or balance. It's not possible to just continue inhaling a person. They would also do something for stopping inspiration. Inhibitory neurons inhibit respiratory muscles and relax those respiratory muscles. Let's now talk about the factors that affect respiratory rate. First up, when there is decrease in the partial pressure of oxygen, this would be observed in cases of hypoxia, this causes an increase in respiratory rate. So again, kapag mababa yung partial pressure ng oxygen, our body would attempt to increase this by also increasing the respiratory rate. or yung paghinga ng isang pasyente. Next, if there is an increase in the partial pressure of carbon dioxide, which is otherwise referred to as hypercapnia, this also causes an increase in the rate and depth of ventilation. Rate and depth. So yung dalas, yung number of inhale-exhale ng isang person per minute, dadami daw po ito. and as well as the depth of ventilation or kung gaano kalalim yung pag-inhale and pag-exhale ng isang pasyente. Again, this happens in cases of hypercapnia or excessive yung partial pressure ng carbon dioxide. Next, if there is a decrease in the partial pressure of carbon dioxide, this would be referred to as hypocapnia. So this causes a decrease in ventilation. So our breathing rate will slow down because we exhale too much carbon dioxide. Next, chemoreceptors in the medulla oblongata and the blood vessels near the heart would respond to the changes in the partial pressure of carbon dioxide and also the blood ph all right so let's repeat it located um within our medulla of longata and also located within um the blood vessels near our heart we have chemoreceptors all right so these are um sensory receptors that would detect if there is any change in the partial pressures of carbon dioxide or your ph of our blood because yung increase or decrease ng carbon dioxide in our blood that also affects our affects affects our blood ph all right so these are the factors affecting respiratory rate next we have what is known as the herring brewer reflex so the herring brewer reflex would limit the depth of inhalation preventing the over inflation of the lungs so yung dahilan daw po kung bakit hindi sumosobra yung pag-inflate nung lungs natin. Yung dahilan daw po kung bakit hindi palaging sobrang lalim nung paghinga natin ay dahil sa herring brewer reflex. Again, this would limit the depth or yung lalim ng paghinga natin and also preventing yung overinflation or sobrang pag-expand ng ating lungs. Again, that is because of the herring brewer. reflex. This slide right here shows us a visual representation of the nervous and chemical mechanisms of breathing. So again, a lot of these things happen within our medulla oblongata or medullary respiratory center. So pinapakita lang naman po dito yung iba't-ibang mga scenarios and yung iba't-ibang mga organs natin that is involved and that may be able to influence our breathing. If you belong to my lecture classes, that ends our discussion on the respiratory system. Thank you so much for listening. If you belong to my laboratory classes, proceed and go through the microscopic anatomy samples that we may be able to observe with regards to the observation of our respiratory system. This slide right here shows us a microscopic view of our nasal cavity. So, our nasal cavity itself, these are the spaces we see here, or the white or blank areas. The nasal septum, this is the part that divides, this is what divides between the two external nares, or the two holes in the nose. Other things that we may be able to see here is the oral cavity. cavity. So right here, ito yung space ng oral cavity and then this organ right here is the tongue. This slide right here shows us three different views of our larynx. Now, if you would remember from the previous discussion, the larynx is otherwise referred to as the voice box, all right? So ayan po. Kaya dito sa isang view, nakakakita tayo ng false vocal folds. and here are the true vocal cords alright now with regards to viewing these samples in scanner mode it's a bit difficult to actually kind of like identify everything so it makes a bit more sense it makes sense that we are looking at a zoomed in view so for this one we are focused on the low power objective So here at the low power objective, we can see that even from the larynx, we may be able to see that this is already lined with pseudostratified columnar epithelium as we can see right here. And it's also ciliated, right? If you would look at this outer edge right here, right? So there it is. Again, pseudostratified columnar cells. They're not actually stratified. Mukalang silang multiple layers kasi hindi sila pantay-pantay ng height or hindi magkakapantay yung... levels or locations of their nucleus. But if you would see the basement membrane right here, all of them are attached to the basement membrane. Right here, we may also be able to observe goblet cells or these white spots right here. Goblet cells, they may be able to produce mucus. They can secrete mucus. Still on the larynx, ito mga views naman po na ito ay nakafocus na doon sa mismong vocal cords natin. Alright, so again, our vocal cords, they're capable of producing sound as air passes through them. So when air passes through them, they would vibrate, creating the sound that we are hearing when we speak. Alright, so as you can see right here, kapag may nakikita kayong gandong itsura, this is the vocalis muscle area. Alright, these areas right here are just ligaments. Next, here's another view showing a tiny segment of the vocalis muscle. And then here outside, we can observe again the usual respiratory epithelium. Again, what is the component of respiratory epithelium? Pseudo-stratified columnar epithelium. Or let's call it pseudo-stratified ciliated. columnar epithelium. This slide shows us a sample of the trachea at low power objective. Now again, what is the trachea made of? It's made of letter C-shaped cartilages, right? C-shaped rings of cartilage. So this is what we see here. Notice this strip of cartilage is lightly curved, right? So again, on this outer portion right here, we would be able to observe the respiratory epithelium. Again, ano ang composition ng respiratory epithelium? Pseudostratified ciliated columnar cells. These kind of like things right here that look like holes, these are blood vessels, all right? So these are the blood vessels that would supply oxygen and nutrients to our trachea. And then these areas right here, this is the hyaline cartilage. So don't forget, our trachea is made up of C-shaped rings of hyaline cartilage. This slide right here shows us an example of the trachea in high power objective. So right here, we're seeing in more detail our hyaline cartilage. And right here, we can see the Pseudostratified Celiated Columnar Epithelium. Again, these empty spaces or holes right here, these are most likely our blood vessels. Alright, so I guess by now, we should be familiar with the appearance of the Hyaline Cartilage and the Pseudostratified Celiated Columnar Epithelium. Because this is not... Before we look at it, we've already talked about this when we discussed tissues and histology, right? So here, we're just learning that these two things together, hyaline cartilage and pseudostratified ciliated columnar epithelium, together they would create our trachea. This slide right here shows us an example of the trachea in oil immersion objective view. Okay, so ayan po, dito kitang-kita na talaga natin yung bawat isa dun sa mga pseudo-stratified ciliated columnar epithelium. And as we can see right here, naka-point out din kung nasan yung area where we would be seeing their cilia or their hair-like structures. Next, since nasa oil immersion objective na tayo, medyo mas nakikita na natin yung connect. tissue components. So these connective tissue components are otherwise referred to as the lamina propia. Next, again, we saw in the previous slides, these empty spaces right here are most likely blood vessels. This slide right here shows us an example of the bronchial and the alveoli in scanner view. So if, for example, this is the bronchial, And right here is a tiny artery or an arteriole. It will continue to branch out to the respiratory duct. So when it reaches the respiratory duct, that's where we'll start to see multiple clusters of alveoli. Again, our alveoli is otherwise referred to as air sacs, right? So there's not a lot of things that we're seeing right here. There's so much empty spaces because these are areas wherein air would pass through. Let's look at this low-power view of the bronchial and alveoli. So it's the same. The bronchial lumen is usually larger, all right? Mas malaking space. sa gitna ng bronchiol kasi nga, parang it's one of the larger branches. And then after that, it branches off further into the alveoli. So nakikita natin dito yung simple epithelium and the alveolar air spaces. Right here, we're also seeing an arterial lumen. So usually, magkalapit or magkatabi po yung mga bronchioles and arterioles. This slide right here shows us the bronchial and alveoli in high power objective. So, ayan po. As you can see right here, if this is the bronchiolumen, alright, this is the bronchiolar epithelium. Now, if we were to compare the bronchiolar epithelium compared sa alveolar epithelium, ayan po, the bronchiolar epithelium is made up of a single layer of cuboidal cells, right? Simple cuboidal epithelium. Look at these cells right here. They're not squamous, right? They're definitely not columnar. So they are cuboidal. Pero, yung mga alveoli po, they're made up of simple squamous epithelium. Bakit ganun? Bakit magkaiba po sila? Because at the alveoli, that's where gas exchange would happen. Di ba po? So it makes sense. It makes perfect sense na mas sumanipis. yung type of cell na pwede natin makita sa paligid ng mga alveoli in comparison to the bronchiolar epithelium. Right here, it's a bit difficult to see some of the simple squamous epithelium of our alveoli kasi po, we're seeing right here na katabi nila yung capillaries, capillaries, and the alveolar walls, and maraming naka-attach na mga. RBCs or marami mga RBCs na malapit sa area na to. So parang natatambakan ng mga RBCs yung ibang structures that we're supposed to be observing. But anyway, kapag nakita kayo ng ganito, most likely these are RBCs meaning that capillaries are nearby. This slide right here shows us an oil immersion objective view of our bronchus. So one of our bronchi. So that's how its composition is. Alright, so it's still composed of that pseudostratified ciliated columnar epithelium. Right here, it points out the specific areas where the cilia is. And then right here, it also shows a goblet cell. The goblet cell right here is a bit lighter staining. It has a lighter stain compared to all the other cells around it. Again, goblet cells are there to produce mucus. Alright. Right here is kind of like a layer of connective tissue. And right here, ito po ay yung mga smooth muscles na. Smooth muscles that would surround the bronchus. And again, smooth muscles are there to help us with either bronchodilation or bronchoconstriction. Kapag bronchodilation, mag-i-increase yung diameter ng bronchus. Kapag bronchoconstriction, mag-i-constrict or liliit. yung diameter ng bronchus, so lilit din yung daanan ng hangin. Again, which medical condition leads to the bronchoconstriction of the terminal bronchioles? It's asthma. Alright, so pag hinihika yung mga tao, nagkakaroon din sila ng episode of bronchoconstriction. This slide right here shows us an example of the bronchus with cartilage at high power objective. So again, same respiratory epithelium. It's made up of pseudostratified ciliated columnar epithelium. Guys, if you've seen these things in upcoming practicals and major exams, you'll notice that there's a lot of different types of bronchus. Medyo nakakaya kasi paulit-ulit ko na pong sinasabi ano ang composition ng respiratory epithelium. It's pseudostratified ciliated columnar epithelium. Isa pa, ulitin natin, pseudostratified ciliated columnar epithelium. Pag yan talaga nakalimutan nyo pa ha. And then right here, we're seeing a bit of cartilage. So again, anong type of cartilage would create? some areas of our respiratory tract. It's hyaline cartilage. Alright? So, again, ulitin natin yung mga cartilage na pwede nating ma-observe sa ating respiratory tract is made up of hyaline cartilage. This slide right here shows us an example of the alveoli in low power objective. Okay? So, dito po, ayan, medyo mas nakikita na natin, no, yung simple squamous epithelium, no? Simple squamous epithelium. that would create each of our alveolus or creating all of the alveoli that we're seeing right here. So all of these empty spaces are the air spaces. This slide right here shows us an example of the alveoli in high power objective with alveolar macrophages. So as we can see right here, there are no macrophages attached to them. ng mga RBCs. So mas nakikita na po natin yung simple squamous epithelium ng alveoli natin. So these are just a single layer of squamous cells. And again, bakit kailangan single layer of squamous cells lang composition ng alveoli? Because this is where gas exchange would happen. So we need a kind of like an epithelium where it could facilitate an easy diffusion of oxygen and carbon dioxide. So again, saan gawa? Saan gawa ang alveoli natin? Sa simple squamous epithelium. And then these ones right here, nakikita natin, these are the alveolar macrophages. So they're present in our alveoli just in case, halimbawa, meron tayong mainhale na infectious pathogens. maybe infectious pathogens out there such as bacteria or fungi, na na-acquire natin sila via inhalation. So minsan, hindi sila natatrap sa hairs ng external nares natin. Minsan, hindi sila natatrap sa mucous, nakakalusot pa sila sa mucous membranes ng nasal cavity natin. So at least, kapag umabot po sila, kapag umabot sila, sa alveoli natin at least no my next line of defense pataya which is our alveolar macrophages now if you would remember our discussion on the human blood right you mga macrophages but they are phagocytes they are phagocytic cells they are capable of phagocytizing or engulfing you mga foreign substances and infectious microbial pathogens all right so again That's the purpose of the alveolar macrophages being inside of our alveoli. That ends our discussion on the respiratory system. I am Aurel Enriquez. Thank you so much for listening.

So after pong makreate ng adenosine triphosphate, ang byproduct nito or ang waste material dito is yung carbon dioxide. And this must be removed from the blood. So excessive accumulation of carbon dioxide could lead to negative effects in the body.

Listed here are the main structural components of the respiratory system. First, yung point of entry po nung hangin na hinihinga natin, this would enter the external nose. So the nose is basically a chamber for the air that we inhale. Next, pagpasok po nung hangin sa ilong, it would pass through the nasal cavity. In this area, we would have nose hairs that would clean the air.

Since the nasal cavity is more in the inner part, this would also warm the air that we breathe in. And also, we have mucous membranes that produce small amounts of fluid in our nasal cavity. So this could also humidify the air that we just inhaled.

For some people, they have a problem in their nasal cavity, which is why they need help from... humidifier okay but for normal healthy people with a perfectly healthy nasal cavity no we don't need external humidifiers so our nasal cavity could do that for us after that the air that was inhaled would travel to the pharynx so this is also known as the throat all right and the pharynx is also a common area where air can pass through and the food that we ingest. After the pharynx, air would travel further down into the larynx, which is also called the voice box.

So, don't forget their common names. Again, the pharynx is the throat, and the larynx is the voice box. So, this is the segment of our respiratory tract that also contributes to our ability to speak. speak by generating our voice. So again, the two main functions of the larynx is for breathing and for voice production.

Paglagpas po ng larynx, next is the trachea. The trachea is also known as the windpipe. Alright, again, wagahalimutan yung common names.

Pharynx is the throat, larynx is the voice box, and the trachea is the windpipe. Of course, sa mga upcoming quizzes, practicals, and exams natin, ang isasagot pa rin po natin is yung mga scientific names nila, okay? Which is the pharynx, larynx, and trachea. Anyway, the trachea, again, this is otherwise known as the windpipe, alright? So, ayan, kadugtong po ng trachea is yung mga bronchus, alright?

So, bronchus, kung isa lang, bronchi, if we're talking about the two of them. All right. So they actually branch from the trachea and then they connect directly to the lungs. Finally, inside of the lungs, there's kind of like a maze or network of tubes where air would pass through. So this network is composed of alveoli, commonly known as the air sacs.

OK, so again, alveoli is otherwise referred to as air sacs. Plus there are. there are also capillaries within that area.

Now if you remember from our past discussion, the capillaries are the places where gas exchange could happen plus being in an area where blood could circulate. So there could be or this could be the place where there would be an exchange between carbon dioxide and oxygen within our blood cells. Alright now in our discussion on the respiratory system. the main site kung saan gas exchange lang talaga yung pakinabang nila would be the alveoli.

Alright? So ulitin natin, sa alveoli po, for the most part, puro pag-enter ng oxygen and pag-exit lang ng carbon dioxide yung ginagawa nila dito sa alveoli. Listed here are the segments of the respiratory system. Simula sa nose hanggang sa larynx, that's the upper respiratory tract.

Again, from the nose to the larynx, that's the upper respiratory tract. Simula sa trachea hanggang sa mga alveoli, that's the lower respiratory tract. Ulitin natin, from the nose to the larynx, that's the upper respiratory tract.

From the trachea... to the alveoli, that's the lower respiratory tract. The conducting zone are the places where only ventilation could happen.

So sa conducting zone daw po, pagdaan lang po ng hangin yung nangyayari dito. Let's compare that to the respiratory zone. So sa respiratory zone naman po dito, gas exchange ang ginagawa nila. Alright, so ulitin po natin, conducting zone, passage of air. only.

No gas exchange. Sa respiratory zone, mostly gas exchange. This slide right here shows us the general structures of the respiratory system.

So of course, as we go through our discussion, iisa-isahin din po natin itong mga ito. Let's now go through some definition of terms. Ventilation is the movement of air in to and out of the lungs.

Alright? So literal na pagdaloy lang po ng hangin. That is ventilation. External respiration is the exchange of oxygen and carbon dioxide between the air in the lungs and the blood. Alright?

So let's compare that with internal respiration. Internal respiration, this is the exchange of oxygen and carbon dioxide between the blood and the tissues. So, kung sa external respiration po, yung air and yung lungs yung nagpapalitan ng carbon dioxide and oxygen, sa internal respiration po, yung blood and tissues naman po yung nagpapalitan ng oxygen and carbon dioxide.

Listed here are the other functions of the respiratory system. Ano pang ibang kayang gawin? ng respiratory system aside from exchanging oxygen and carbon dioxide.

The respiratory system can maintain the pH of the blood by getting rid of the excess carbon dioxide. So first question, ano ba ang normal pH ng blood? Alright, so it's at 7.35 to 7.45, which is slightly alkaline.

Ngayon, ano naman po? kung tataas yung carbon dioxide in the blood. Now, this could result in hypercapnia or respiratory acidosis.

Now, patients with hypercapnia can present with tachycardia, dyspnea, confusion, headaches, and dizziness. So, let's define some of those. Tachycardia is a heart rate that is faster than normal or more than 100 beats per second. per minute at rest okay so based on our um previous discussion on the cardiovascular system yep it's at 72 beats per minute only all right next dyspnea so dyspnea this is a sensation of running out of air and of not being able to breathe fast enough or deeply enough so In simpler terms, just to simplify that statement, nahihirapang huminga.

There is difficulty breathing. So dyspnea, difficulty breathing. Next additional function of the respiratory system is the production of chemical mediators.

So the lungs can produce the enzyme ACE or the angiotensin-converting enzyme. Angiotensin-converting enzyme. also has the capability to regulate blood pressure.

Alright? So may enzyme din daw po na pinoproduce yung respiratory system natin na kayang maapektuhan or kontrolin yung cardiovascular system natin, specifically our blood pressure. Next is voice production thanks to the larynx. Alright? So again, ano po ang common name ng larynx?

It's the voice box. Okay? So as air moves through the larynx, nasa larynx po kasi yung vocal cords.

So the vocal cords are the muscular tissues that are folded in a V shape. So dun sa vocal cords, sound is created. Other functions of the respiratory system include olfaction or the ability to smell. So, as we inhale, scent particles are also brought in. So, kasama ng hangin.

So, the sensory neurons that our nasal cavity would detect and send signals to the brain. So, ulitin po natin, pag-inhale natin, may kasama yun na mga scent particles or mga chemical stimuli. So that would reach the olfactory nerves on our nasal cavity and send those signals to our brain.

Next is protection. So the respiratory system provides protection against some microorganisms by preventing them from entering the body and removing them from the respiratory surfaces. So that's the reason why nose hairs at the entrance of our nasal cavity are present all right para pag may na inhale po tayo no kung para pag inhale natin kung may mga dust particles or pollution kasama dun sa hangin merong mga infectious organisms no at least na filter muna sila no mga hair strands present at the nasal passage so if ever po may mga microscopic infectious organisms na nakalagpas sa nose hairs natin Ang next level naman po is the mucous membranes of the nasal cavity.

So they're supposed to stick or to be trapped by the moisture or mucous in the nasal cavity. Tapos eventually, iahatching or isisingan na lang po yung mga particles na yun. Nabanggit na po natin ito kanina on the...

previous slide, here are the components of the upper respiratory tract. The external nose, the nasal cavity, the pharynx, and the larynx. Let's go through all of those parts one by one, starting with the external nose.

So the tip of the external nose is mainly composed of hyaline cartilage. Okay, let's repeat. The tip of the external nose is made of hyaline cartilage all right so which is why it's um quite soft and has flexibility all right so when we die it would also rot away along with our soft tissues all right so you miss moon bone pot and skull the makita puna thing that be beginning shape so no snuff and would start at the nose bridge and then after that it's just hyaline cartilage Next is the nasal cavity. So it extends from the naris or the nostrils to the troana or the entrance, yung papunta na sa pharynx.

Yung taas naman po, this is called as the hard palate and yung cartilage dito sa gitna that divides the two holes of the nose is called the nasal septum. Next part of the nose are the paranasal sinuses. So the paranasal sinuses are the openings to the nasal cavity. And this is the place that is lined with mucus.

So if you would remember from our previous discussion, these kinds of mucous membranes, they're considered as the first line of defense and is part of our innate and non-specific immunity. Next is the concave. So the concave, these are the bony projections on each side of the nasal cavity. So sa loob daw po ng nasal cavity, meron parang pader kung saan may mga nakaprotrude na mga bones.

Alright, so these protrusions would increase the surface area of the nasal cavity. The greater the surface area means that the air from the outside would have more places or areas in our nasal cavity to make contact with. which would help it in warming up the air from the outside. Last part of the nose is the nasolacrimal ducts, also known as tear ducts. So ito daw po yung daanan ng luha and connected din daw po ito sa nasal cavity.

Again, that is referred to as the nasolacrimal ducts. Listed here are the functions of the nasal cavity. This would remain open even when the mouth is full of food. Okay, so dalawa po yung pwedeng daanan ng hangin na hinihinga natin, the nose and the mouth.

But breathing through the mouth is not really a good practice. Okay, pero ayan niya po in cases of people who are mouth breathers, at least even when their mouth is filled with food. food, the air can still pass through. Next, the nasal cavity could clean the air that we breathe in.

This is because of the hairs which would trap large dust particles and the mucous secretions that could catch the smaller particles. Third function is to humidify and warm the air, which again is a function of the conque. Our nasal cavity is also the area where our olfactory epithelium is located, which again is very important to be able to smell.

Next, it helps determine how our voice would sound. So the nasal cavity and the paranasal sinuses are the resonating chambers for speech. So basically, our voice sounds like this because of the way that the air has passed through our nasal cavity. nasal cavity and paranasal sinuses which is why when we have a sore throat, for example, we have a sore throat, the sound of our voice changes.

So again, that's one of the reasons because it's part of the function of the nasal cavity. Again, the nasal cavity and paranasal sinuses determine the sound of our voice. So again, when we are sick or if for example our nasal passages or nasal cavity is blocked, all right this could affect the sound of our voice let's now talk about the next segment of our upper respiratory tract which is the pharynx all right so again the pharynx is otherwise referred to as the throat and this is the common passageway for the respiratory and digestive systems all right so again pharynx can go through both air and food so the pharynx is actually divided into to three segments or three areas. First up is the nasopharynx.

So as the name implies, ang katapat nito is the nasal cavity. So this would take in the air that we inhale. Next is the oropharynx.

As you would expect, ang katapat po nito is yung oral cavity. So this extends from the uvula to the epiglottis. Next is the laryngopharynx. So the laryngopharynx the laryngopharynx would extend from the epiglottis up to the esophagus.

Next, what is the uvula? The uvula is otherwise referred to as a little grave, which is the extension of the soft palate. So, this is the most well-known structure that we usually refer to as the tonsil.

But if you would remember our discussion on the lymphatic system, there are three different types of tonsils. Now, for our discussion on the respiratory system, we will only be mentioning the pharyngeal tonsil. So within the pharyngeal tonsil, we can see the structure of the uvula.

So the pharyngeal tonsil... Now this aids in defending against infections, which again we've already mentioned that when we discuss the lymphatic system. This illustration right here shows us all the specific structures that we may be able to find within our nasal cavity and our pharynx.

So dito pa lang po, nasal cavity and pharynx pa lang, napakarami ng mga specific parts na kailangang aralin. The third component of the upper respiratory tract is the larynx. Again, this is otherwise referred to as the voice box. So this is located in the anterior throat that extends from the base of the tongue to the trachea.

So let's repeat the area where the larynx is. It starts at the base or below the tongue until the trachea. So the larynx consists of nine cartilages. So, ayun po. we have what is known as the thyroid cartilage.

So the thyroid cartilage, this is the largest piece of cartilage that is attached to the larynx. And this is referred to as the Adam's apple. So in males, this is referred to as the Adam's apple.

Now in females, the thyroid cartilage is not that prominent, so it doesn't have a specific name for females. Let's just clarify this, alright? Lahat ng tao Regardless whether you are a male or female, lahat po ng tao, everybody has a thyroid cartilage. Okay?

So again, everybody, regardless of gender or biological sex, no? Everybody has a thyroid cartilage. It's just that it is a bit more prominent in males.

So yun po yung na-observe natin na Adam's apple. Alright? So wala tayong nakikita na Adam's apple in females because their thyroid cartilage.

is not that prominent or not that large, all right? But it is there. It is present, all right? Females also have a thyroid cartilage, but it is not as protruding or as prominent as that of males.

So again, the Adam's apple is another term, just another term for the thyroid cartilage. Another part of the larynx is the epiglottis. So this is a...

piece of cartilage that looks like a flap, alright? So this flap would prevent swallowed materials from entering the larynx, okay? So let's repeat, the first part before it reaches the larynx is the pharynx, right?

And the pharynx is the common area where both air and food items could pass through, right? So there, again, the advantage of epiglottis is to flap and cover, right? To cover the larynx so that food particles will not accidentally pass through the larynx, which the next segment is trachea.

So again, the epiglottis serves as some form of covering to prevent the entrance of food items that came from the pharynx. This slide right here shows us all the other specific parts and the other types of cartilage that would make up the larynx next next are the vestibular folds so the vestibular folds these are just false vocal cords next are the vocal folds so the vocal folds these are the actual sources of voice production all right so need to put a vocal folds when air moves pass them, so kapag dumaan daw po sa vocal folds yung hangin, they would vibrate, and then sound is produced. Okay?

So again, sound is being produced through the vibration of our vocal folds. They vibrate as air passes through. So, the force of the air determines the loudness of our voice. Alright? Yung puwersa daw po ng hangin, this would help us adjust kung gano kalakas or kung gano kahina yung boses natin.

Now the tension that we produce on our throat, the tension would determine the pitch of our voice or kung gaano katinis or kung gaano kalalim yung boses natin. This slide right here shows us a visual representation kung saan po located yung larynx natin, which again is right here, simula sa base of the tongue. Next, here is an illustration of all these structures.

that we've talked about earlier and right here is an actual photo of our larynx through superior view. Let's now go through the parts of the lower respiratory tract starting with the trachea and then the bronchi, tracheobronchial tree in the lungs, and then the alveoli. Again this illustration right here just visually shows us where our upper And lower respiratory tract would be located and kung ano po yung mga components nila.

Again, the upper respiratory tract is composed of the nasal cavity, pharynx, larynx, and syempre kasama dito yung entrance which is the external nose. Next, the components of the lower respiratory tract would be the trachea, bronchi, and the lungs. And of course, yung mga alveoli na nandito po sa looban ng lungs. First structure at the lower respiratory tract is the trachea, commonly known as the windpipe. So this is made up of 16 to 20 letter C-shaped rings of cartilage, and those rings are called tracheal rings.

So let's repeat, these 20 letter C-shaped cartilage are called tracheal rings. So if we arrange them together, this will create the trachea. Given here are other facts about the trachea.

So this is lined with pseudostratified columnar epithelium. Again, if you would rewind to our discussion on tissues and histology, kapag sinabi po natin na pseudostratified columnar, they only look like they are stratified or they falsely look like they are multiple layers. Pero hindi po talaga. They're just varying in...

They're varying in... in sizes, and also the locations of their nucleus. So, it's like their appearance is not even, that's why they're called stratified.

But in general, they are columnar, meaning they are cells that are taller in comparison to their width. So, let's repeat, the trachea is lined with cells that are referred to as pseudostratified columnar epithelium. Now the problem here is that smoking could kill the cilia. So basically, in Tagalog, pinuponpon or sinisira daw po ng habit of smoking yung hair-like structures sa ibabaw ng pseudostratified ciliated colunar epithelium. Next, coughing dislodges materials from the trachea.

So kung halimbawa naman po may foreign materials, foreign particles, or irritated particles. that passed through our windpipe. Then what would happen is the natural reaction of our respiratory system would be to eliminate those or to get rid of those through coughing. This illustration right here shows us the anatomy of the trachea and the lungs.

Alright, so again there are different parts right here that has been labeled. What we see here are white spots. Dito, ito po yung mga cartilage or yung mga C-shaped cartilage that would create the trachea. Now, as you can see right here, the air passageway would decrease in size.

Notice, no, na in terms of the diameter, no, visually, mas malaki talaga yung daanan ng hangin simula dito sa larynx hanggang sa trachea. But they decrease in size but increase in number as we go. go to the inside of the lungs. So as we can see right here, the passageways will become smaller and smaller, but the branches would continue to divide. So again, don't forget to study the parts and labels that we see here.

Next stop is the bronchi. This is basically an extension of the trachea because it's also... made up of the same letter C-shaped cartilage, but it branches into the left and right bronchi that would directly connect to the left and right lungs. So just like trachea, this is also lined with cells that have cilia. This slide right here just lists down the components of the tracheobronchial tree.

So we mentioned earlier, right? structures would become smaller and more numerous from the primary bronchi to the alveoli. So, from the larynx to the trachea, the passageway for the air is a bit wider. As we move to the inside of the lungs, the passageway gets smaller, but at the same time, there are more branches. Alright, so first up we have the primary bronchi.

So, this would be further divided into the... lobar or secondary bronchi, the segmental or tertiary bronchi, until eventually it branches off into the tinier bronchioles, all right? After that, we have the terminal bronchioles and then the respiratory bronchioles. So, tuloy-tuloy lang po.

Branch lang ng branch hanggang umabot sa alveolar ducts and the alveoli, okay? So, pagdating po sa alveoli, This is again not otherwise referred to as the air sacs where exchange of gas or gas exchange would actually happen. This slide talks about changes in air passageway diameter.

Bronchodilation happens when the smooth muscles around our bronchioles relax, allowing our airways to be larger in diameter. So basically, mas maluwag po yung daanan ng hangin. Bronchoconstriction happens when the smooth muscles around our bronchioles contract, making bronchial diameter smaller.

Dito naman daw po sa bronchodilation, imbis na relax, nagkokontract daw po yung smooth muscles sa paligid ng mga bronchioles. So sumisikip din daw po yung daanan ng hangin. Next, what happens during asthma attacks?

This is the contraction of the terminal bronchioles, resulting in reduced airflow. So basically, the bronchoconstriction also affects the people who are breathing, so they have a hard time breathing. Let's now talk about the alveoli.

So the alveoli are the sites for external respiration. All right. So the alveoli are otherwise referred to as our air sacs. All right. So small air filled sacs where air and blood would come into close contact.

And this is where gas exchange would happen. All right. So our alveoli, they're actually surrounded by capillaries.

According to this slide, simula daw po sa terminal bronchioles natin, there are multiple levels of branching. Alright, so this is something that we've always mentioned simula kanina, di ba? Na simula sa larynx and trachea, there is a wide diameter of passageway for the air. Pero as we move through, lumiliit yung mga daanan ng hangin, but at the same time, there's continuous branching.

So ganun din po dito, there are multiple levels of branching. Especially when we start or when we come from the terminal bronchioles. So first up, we have what is known as the respiratory bronchioles. So they have a few alveoli.

Alright, so a few alveoli are attached to them. Next, we have the alveolar ducts. So they arise from the respiratory bronchioles and open into an alveoli.

So let's repeat. Starting from the terminal bronchioles. may respiratory bronchioles. Simula sa respiratory bronchioles, meron ng konting mga alveoli.

Pero, if we like further go through the branches, simula dito sa respiratory bronchioles, magpa-further divide pa ito into alveolar ducts. So, dito po nag-open up na siya into other alveoli. Next are the alveolar sacs. So, these are the chambers connected to two or more alveoli. at the end.

Alright, so sa alveolar sacs po dito, ayan niya, medyo mas marami na tayo makikita ng mga alveoli dito. So we would understand this better as we look through the illustration on the next slide. This slide shows us all the structures that we've discussed in the previous slide. So again, if for example, this is our terminal bronchiole, this would further divide into the respiratory bronchioles or these three segments or divisions right here.

So itong mga respiratory bronchioles, it has been described that they have a few alveoli attached to them. So may mga pa-isa-isa na tayo makikita dito. So as you can see right here in this label, right here we're seeing one alveolus.

Okay, so kapag isa niya lang alveolus, kapag madami sila, alveoli. Okay. Next, the respiratory bronchioles with further branch into the alveolar ducts. So, pagdating sa alveolar ducts, tuloy-tuloy na siya hanggang sa alveolar sacs.

Alright, so dito sa alveolar sacs, definitely, mas marami na tayong ma-observe na alveoli as we can see right here in this illustration. And of course, the alveoli are also surrounded with a network of capillaries. capillaries, as we can see right here in this illustration. So these ones right here are labeled as the pulmonary capillaries. Let's now talk about the respiratory membrane.

So the respiratory membrane is found in the lungs, and this is where gas exchange between the air, yung hangin, nakakainhale lang natin, and the blood would occur, right? So the respiratory membrane is formed by walls of alveoli and capillaries. So, yun nakita po natin dun sa previous illustration kung saan may mga alveoli na nababalutan ng mga capillaries. So, yun po, we would refer to that area as the respiratory membrane. So, alveolar ducts and respiratory bronchioles would also contribute to these activities of exchanging gases.

So, ayun po. The respiratory membrane is observed to be very thin for the easy diffusion of gases, which makes sense. It needs a single layer of cells to pass through the gases so that they can easily pass through from one area to another. So for example, the oxygen needs to be able to diffuse or move from the alveoli to the other.

sa blood circulation. And the other way around, kung may carbon dioxide po na nandoon sa blood circulation, dapat madali lang din para sa kanya to exit the capillaries and move into the alveoli in preparation for exhalation. So again, it makes sense that they are very thin for the easy diffusion of gases. Listed here are the layers of the respiratory membrane. So again, let's focus on the specific layers with highlights.

First is the alveolar epithelium. The alveolar epithelium is made up of simple squamous epithelium, which again is only composed of a single layer of cells. Next, it has a thin interstitial space.

And next, it has a basement membrane of capillary endothelium. This is also made up of simple squamous epithelium. So again, like what we mentioned in the previous slides, you really need a single layer of cells for the passage of gases for easy diffusion. This illustration right here shows us the alveolus and the respiratory membrane. So if, for example, the airspace within our...

alveolus. Ito yung mga areas kung nasaan pwede tayong makakita ng mga capillaries or kung saan pwedeng dumadaan yung mga RBCs. Now, if we were to zoom in further in this area, makikita natin na kung halimbawa ito yung airspace ng alveolus, ito naman po yung respiratory membrane or yung area kung saan mahanap natin yung blood circulation.

So again, there's only a simple example. squamous epithelium between these two structures. So again, they should be simply layered so that the diffusion of oxygen can be easily diffused to the RBCs and the diffusion of carbon dioxide from here to the alveolus.

So when the carbon dioxide goes to the alveolus airspace, it's ready to be exhaled. All right. So again, if you belong to my laboratory classes, huwag pong kakalimutan na aralin itong mga parts that have been labeled right here.

Let's now look at the anatomy of the thoracic wall. It's composed of multiple structures like the thoracic vertebrae, the ribs, the coastal cartilages, the sternum, and all the muscles that are attached to these areas na tumutulong para makapag-move yung thoracic wall whenever we breathe in or we breathe out. Alright, so of course, since our lungs expand and contract when we inhale and exhale, it's important that there are associated muscles here to help with that expansion and contraction of our lungs.

The thoracic cavity is a space enclosed by the thoracic wall and diaphragm. So, all the structures structures that we enumerated earlier plus the diaphragm underneath that, this would create the space that is referred to as the thoracic cavity. So we discussed this when we talked about the muscular system. The diaphragm is a skeletal muscle involved in normal quiet breathing.

Let's now talk about the lungs. So the lungs is the primary organ of respiration. Alright?

So marami tayong na-discuss kanina, diba, ng mga ibat-ibang parts, ibat-ibang segments that would create our upper and lower respiratory tract, right? But the main organ that is responsible for our breathing is the lungs. Another description said here is that it is cone-shaped, alright? So medyo pointed yung itaas, tapos mas malapad yung ibaba. Alright, so again, the lungs is somewhat...

cone shape. Next, the base rests on the diaphragm. Alright? So yung base daw po, ito yung area that is within contact on top of the diaphragm. Alright?

And the apex extends above the clavicle. So yung apex or yung slightly pointed part daw po nung lungs natin. So nag-extend daw siya.

Medyo mas mataas ng kaunti sa clavicle natin or dun sa collarbone. Our clavicle is otherwise referred to as the collarbone. So the right lung has three lobes.

So it seems like there are three more segments of the right lung. Meanwhile, the left lung only has two lobes. So on the next photo, we will see that. These illustrations right here shows us the lungs, their lobes, and the bronchi.

all right so this one is the right lung and this one is the left lung all right so right here on top The one that is seen to be a little bit pointed, that is the superior lobe. Then let's move to the right. So on the right, it has three lobes.

So if this is the superior lobe, right here it has what is known as the horizontal fissure, dividing the middle lobe. So the middle or the second lobe is right here. Next, it has what is known as the oblique fissure. And then, this would show us that it is here on this side, the inferior lobe or the lobe that is below or closer to the base.

Okay? So, there. Again, superior lobe, middle lobe, and inferior lobe. These are the components of our right lung. In comparison to the left lung, the left lung only has two lobes.

Alright? It doesn't have a middle. Okay? It's just the superior.

and the inferior lobe. Alright? And as we can see right here, we have areas that are referred to as the cardiac impression, cardiac notch.

Alright? So, ito po yung areas, most likely, kung saan nakaharap yung apex nung heart natin. Diba?

If you would remember our discussion on the heart, diba po? The heart is located in the middle of our two lungs. Pero yung apex po nung heart, no?

The apex of the heart is facing towards the left lung. Alright? Kaya po, mas na, mas na dedetect natin yung heartbeats ng isang pasyente by checking the left side of their chest.

And ayun nga po, there are cardiac impressions and cardiac notches on the left lung to make space or to make way for the apex of the heart. Alright? So again, this is the structure of the right lung and left lung.

Let's now talk about blood flow to the lungs. So oxygenated blood has passed through the lungs and picked up CO2. So again, definition of terms.

Kapag sinabi natin na oxygenated na yung blood, oxygenated blood means that nakadaan na po siya sa lungs. So nakahingi na siya ng oxygen. On the other hand, kabaliktaran po nito is deoxygenated blood.

So kapag sinabing deoxygenated na po yung blood supply, It has already gone through the tissues. So, dumaan na siya sa systemic circulation natin. Dumaan na siya sa lahat ng iba't-ibang tissues natin. And it has already released some of its oxygen content.

So, basically, naipamigay na po niya yung oxygen na meron siya. So, it's now referred to as deoxygenated. Alright? So, ulitin natin.

May oxygen pa, oxygenated. Wala ng oxygen, deoxygenated. Next. Pulmonary capillaries would carry the deoxygenated blood to the pulmonary arteries.

Pulmonary arteries would carry the deoxygenated blood to the pulmonary capillaries. So again, huwag pong malilito. Yung pulmonary arteries, sila yung magdadala ng deoxygenated blood papunta sa pulmonary capillaries. After that, the blood would become oxygenated and return to the heart through the pulmonary veins.

Alright? So again, if you would remember one of the illustrations that we've seen earlier, right? The pulmonary capillaries. These are the capillaries that are right next to our alveoli.

Alright? So, the respiratory membrane is here where gas exchange would happen. Right?

So, that's what happens. Alright? So, if it's already delivered or if it's already entered the pulmonary gap.

arteries, the deoxygenated blood, the blood that is already depleted from the pulmonary arteries, the oxygen supply, will reach the pulmonary capillaries. When it comes to the pulmonary capillaries, they will gas exchange, the blood will be given its carbon dioxide and then it will receive the oxygen. After that, the blood would now become oxygenated again and this would return to the heart by passing through the pulmonary veins. Let's now talk about the lymphatic supply to the lungs. Alright, so first up is the superficial lymphatic vessels.

So this surrounds each lung. Alright, so basically, it's just surrounded by the lungs. Meanwhile, the deep lymphatic vessels would follow the bronchi. Alright, so may mga lymphatic vessels din po tayo.

na sinusundan niya yung bronchi papasok doon sa lungs. Alright, so that's the difference between superficial and deep lymphatic vessels on the lungs. Let's now talk about plural membranes and plural cavities. Alright, so yung plural cavity po, this is the space around each lung. Alright, so again, ang keywords po natin dito, kapag sinabing cavity, this is a space.

Alright, so yan po, tinawag siyang plural cavity because this is a space specifically around each of our lungs. Next is the pleura. So the pleura, this is a double-layered membrane. that surrounds the lungs so there are two types of pleura okay so first up is the parietal pleura so the parietal pleura this is the membrane that lines the thoracic cavity okay so ito po yung parietal pleura no naka attach siya dun sa thoracic cavity let's compare that to the visceral pleura the visceral pleura is a membrane that covers the lungs surface so yung visceral pleura Alright, this is directly attached to the lungs. Alright, so there.

When we say parietal, the surroundings are what it holds or wraps. When we say visceral, the same organ wraps this membrane. So again, when we say parietal pleura, this would line the thoracic cavity. But when we say visceral pleura, this would cover the surface of the lungs.

This is directly attached. on the surface of the lungs. This illustration right here shows us a superior view of our lungs.

So if we were to look at this illustration right here, if we were to make this cut right here on top, what will happen is we will be able to visualize the lungs in this specific angle or in this specific view. So as we can see right here, Imagine that the person is facing you. So yung likod niya, nandito, alright? Andito yung vertebra.

Yung harap niya, nandito. Kasi nandito yung sternum. Alright? So ayan po. Magtatandaan yung locations ng parietal pleura, pleural cavity, and yung visceral pleura.

So yung parietal pleura, naka-attach siya or ang kinukover niya is yung lining ng thoracic cavity. Yung pleural cavity, yun yung space sa pagitan nila. This is the visceral pleura.

This one is a membrane that is directly attached to the surface of the lungs. Let's now talk about the process of ventilation or simply breathing. So this is the process of moving air in and out of the lungs. So that's how simple it is. The air flowing as we inhale and the air flowing as we exhale.

That's it. That's what we mean when we say ventilation. So there are two aspects of ventilation.

This may be brought about by the action of the muscles of respiration. So yun nabanggit natin kanina na yung diaphragm and then the muscles within our thoracic cavity or thoracic wall. Next, air pressure gradients. So ito po yung dalawang factors that influence our ventilation or breathing.

Listed here are the muscles of inspiration, otherwise referred to as inhalation. Alright, so ito daw po yung mga muscles na tumutulong sa atin na mag-inhale. Alright, so this increases the volume of the thoracic cavity. So listed here are all the muscles that would help us inhale.

The diaphragm, external intercostals. pectoralis minor, and scalene muscles. Alright, so don't forget, enumerated here are all the muscles that would help us inhale. Let's now talk about the muscles of expiration or the muscles that would help us with exhalation. So these ones would decrease the thoracic volume by depressing the ribs and the sternum.

Alright, so basically, these muscles are compressed. yung ribs and sternum natin kind of like giving a squeezing motion to our lungs to help us exhale all right so the internal intercostals the transverse thoraces and the abdominal muscles these are the three muscles that are involved in expiration or exhalation all right let's repeat the muscles that are involved in exhalation would include the internal intercostals transverse thoracis, and abdominal muscles. Let's now talk about quiet in comparison to labored breathing.

So in quiet breathing, expiration or exhalation is a passive process. So when we say passive, we don't have to consciously think about it anymore. We just breathe normally without attempting to control our rhythmic breathing. So let's compare that to labored inspiration or labored expiration. All right.

So in labored. inspiration, more air moves into the lungs because the inspiratory muscles are more active. Alright, so here, our muscles that are involved in inhalation work more, that's why more air enters our lungs. Next is labored expiration or labored exhalation. So with this one, more air would move out of the lungs because of the forceful contraction.

of the internal intercostals and abdominal muscles. So, dito po, in-specify nila yung dalawang muscles that is involved in labored exhalation. Alright?

So, again, mas maraming air yung lumalabas sa lungs natin because of the contraction of the internal intercostals and abdominal muscles. Inspiration or inhalation happens when the thoracic cavity volume increases. So basically, the space of the thoracic cavity expands. Another thing that happens during inhalation or inspiration is the atmospheric pressure is greater compared to alveolar pressure. So the atmospheric pressure is stronger, the force of the air entering our lungs is stronger.

So air moves into the alveoli. So that's what happens during inspiration or inhalation. Next, expiration or exhalation happens when the diaphragm relaxes and the ribcage recoils. So what happens here is that the thoracic cavity volume decreases.

The space of the thoracic cavity decreases. So the thing that we would be able to observe here is that the alveolar pressure is greater compared to atmospheric pressure. So the force of the air that comes out of our alveoli is higher compared to the air that comes in from the outside. So what would happen here is air would move out of the lungs.

So again, that's what happens during expiration or exhalation. Alveolar ventilation is the measure of the volume of air that is available for gas exchange per minute. Now, we need to take note that there is an area within our lungs where no gas exchange would happen. And this is referred to as the dead space.

Let's repeat it. There is an area or place in our lungs where no gas exchange happens. And that place is referred to as the dead space. Listed here are the different factors that affect our ventilation or breathing, right? So gender, age, body size, and physical fitness, right?

So again, gender, age, body size, and physical fitness are the things that we could consider or factors that we need to consider that would affect our breathing, right? So emphasis on body size and physical fitness because these two are the most readily observable among the fact of... among these four factors that would affect our breathing.

Lung recoil is the tendency for an expanded lung to decrease in size. So basically, pag sinabi pong lung recoil, kapag katapos nating mag-inhale, mag-expand yung lungs. But after nating mag-inhale, kailangan niyang bumalik to its original size.

So the expanded lung would decrease in size. And this happens during quiet breathing. expiration or quiet exhalation right so long recoil is brought about by the elastic fibers and the thin film of fluid lining our alveoli so nagging possible in a book along recoil because of the elastic fibers and film of fluid in like that is lightning that is lightning our alveoli Next, what are surfactants?

Surfactants is a mixture of lipoproteins, alright? Lipids and proteins. So this is produced by secretory cells of the alveoli, alright? So ano po ba ang mga surfactants? This is a fluid layer on the surface lining the alveoli, alright?

So there's a small amount of fluid daw po sa mga alveoli natin and it reduces surface tension and keeps our lungs fluid. from collapsing all right notice our lungs is basically um a place that is filled with air sacks all right so na paka spaces that's just filled up with air so back at hindi ito basta basta nagko collapse or na na de de form nagi squish no um as time goes by or as we um kind of like strain our lungs all right so again This happens because of the presence of our surfactants. All right.

So again, surfactants, they are made up of lipoproteins. They are produced by secretory cells of the alveoli, and they form a fluid layer that prevents the lungs from collapsing. Let's now talk about gas exchange in the lungs. So blood returning from the tissues and entering the alveoli in the lung has a lower partial pressure of oxygen. So let's repeat that statement.

The blood from the tissues is deoxygenated. They don't have any more oxygen with them. So that means they have a lower...

partial pressure of oxygen kasi nga halos wala na silang oxygen na dala and a higher partial pressure of carbon dioxide right so um oxygen diffuses from the alveoli all right so mula daw sa alveoli magde-diffuse or pupunta sa blood natin yung oxygen and then um kabalik na rin nito co2 diffuses from the capillaries okay so ili-let go nung blood cells natin yung carbon dioxide na meron sila, and ipamimigay nila ito papunta sa alveoli para may exhale na natin. That was for the gas exchange in the lungs. Let's now talk about gas exchange in the tissues.

So blood traveling from the lungs, okay? So yung blood nanggaling na daw sa lungs. So nakahingina sila ng oxygen.

Diba po? They have a higher partial pressure of oxygen. Alright, so mas mataas daw yung partial pressure of oxygen nila kasi nga po, diba, may bit-bit na sila or may daladala na silang oxygen molecules and they have a lower partial pressure of carbon dioxide kasi diba, what happened earlier in the lungs?

Pinamigay na nila dun sa alveoli yung carbon dioxide that they were previously carrying. Okay, so oxygen diffuses from the capillaries into the interstitial fluid. When there is gas exchange in the tissues, pagdating po sa mga specific tissues ng blood flow natin, ipamimigay na niya or ididefuse na niya yung oxygen galing sa capillaries and mapupunta na ito sa interstitial fluid.

On the other hand, CO2 diffuses from the interstitial fluid into the blood in the capillaries. So, ang mangyayari, yung mga... carbon dioxide produced by our cells and tissues they will exchange it to the blood present in our capillaries to deliver it back to our lungs to exhale the carbon dioxide from our lungs let's now talk about respiratory membrane thickness so increased thickness decreases rate of diffusion. Alright? So, one thing that we've already mentioned earlier, is the structure of our alveoli and capillaries.

Alright? Or yung respiratory membrane. So, both of them, they have simple endothelium. Simple squamous endothelium.

So, manipis na layer lang po ng cells para easy yung diffusion ng gases. Now, what happens here is that if... For example, a person is experiencing pulmonary edema, meaning there is accumulation of fluid in the lungs.

This would decrease diffusion. So, the diffusion of gases is a bit slow if a person has pulmonary edema. So, the rate of gas exchange is decreased.

So, oxygen exchange is affected before carbon dioxide because carbon dioxide diffuses more easily than oxygen. So kapag may pulmonary edema daw po ang isang pasyente, mas nagiging apektado or mas nauunang bumagal yung pag-diffuse ng oxygen kasi medyo mas mabilis daw pong i-diffuse or i-release ang carbon dioxide compared to oxygen. Let's now talk about hemoglobin.

Now if you've already watched our discussion on the human blood, Review na lang po ito sa atin. Diba? So hemoglobin, this is a protein that occupies about one-third of the total volume of the cytoplasm of red blood cells or RBCs.

Alright? So again, if you would remember the structure of RBCs, they are a biconcave disc with no nucleus. Diba?

So hindi na po kailangan ng mga RBCs ng nucleus. Alright? So that entire area is now filled up.

with hemoglobin. So hemoglobin. consists of four units, each containing one iron-based heme group which binds to oxygen.

Okay? So, ulitin natin, o, or reviewin natin kung aning structure ng hemoglobin. It is composed of four globin molecules.

Diba? Tapos, sa bawat globin molecule, may naka-attach na heme. Sa bawat heme molecule, meron naka-attach na iron.

Alright? And dun sa iron molecule, dun... mag-attach yung oxygen.

Doon magbabind yung oxygen para mabit-bit ito ng red blood cells. So, ayan po. Let's now talk about the regulation of ventilation or regulation of breathing.

The respiratory rate or breathing rate is regulated to maintain gas concentrations. So, hindi daw po mabuti. na sobra yung pag-inhale natin, di rin naman mabuti na sobra yung pag-exhale natin. So, of course, our breathing needs to be regulated. So, there are neurons in our medulla oblongata that control the rate of ventilation through stimulation of the muscles of respiration.

Alright, so ulitin po natin yung part na yun sa medulla oblongata natin. At our brain, there are neurons within our medulla oblongata. where they control the muscles of respiration.

So they control the muscles that are involved in inhalation and the muscles that are involved in exhalation. So again, this happens in the medulla oblongata. Let's talk more about that medullary respiratory center.

So again, the medullary respiratory center is located at our medulla oblongata. And it has two components, right? The dorsal respiratory group or DRG and the ventral respiratory group or VRG.

Okay? So yung dorsal respiratory group na po, this is most active during inspiration. Okay? So mostly kapag nag-i-inhale tayo, ang nagtatrabaho po dito is yung dorsal respiratory group. Meanwhile, yung ventral respiratory group na po, this is active during inspiration.

inspiration and expiration. So both for inhaling and exhaling, what it works for is the ventral respiratory group. Another thing about the ventral respiratory group is that it contains the pre-Bertzinger complex, which is believed to establish the basic rhythm of respiration. constant rhythm of our inhale exhale, pre-Botzinger complex was established.

What is the pre-Botzinger complex anyway? The pre-Botzinger complex or pre-Botz C is a neural network that is responsible for inspiration during respiratory activity. This is the part of the V.R.G. that is involved in inspiration or inhalation. is ito sa mga bagay na um kumbaga is parang may control yung pre-BOTC all right so in 1991 medyo recent pa po ito no in 1991 the pre-BOTC was described as a region of the ventral medulla of longata containing the neural pathway that is necessary to generate respiratory rhythm all right so ulitin po natin yan kung na-confuse kayo sa statement na yun nung 1991 no they discovered the pre-Botzinger complex.

So this is the part in the ventral area of the middle of the lung. They have been able to find out that this is the part of our brain that is responsible for creating our respiratory rhythm. Or the rhythmic inhale-exhale.

This slide right here shows us the location of our medullary respiratory center, which is right here. And then, it teaches us where the specific muscles or specific areas that are influencing our medullary respiratory center to help us with inhalation and exhalation. Let's now talk about the generation of rhythmic ventilation.

Alright, so how does the rhythm of breathing in and breathing out create? First up, we would have the starting inspiration. So the medullary respiratory center establishes the basic rhythm of ventilation. Alright, so this would receive stimulation from the receptors for blood gas levels. So for example, Is the oxygen level too high?

Carbon dioxide levels? Those types of things. Another thing that they would be considering is blood temperature.

Next is the movements of our muscles and joints. So of course, the movements of our muscles and joints would require energy. And energy would be created with the help of the oxygen supply. Again, movements of muscles and joints that would also affect our starting inspiration.

And of course, emotions. There are people out there that when they're experiencing certain emotions, their breathing also changes. Example, kapag ginakabahan yung isang tao, lumalalim yung paghinga nila. Another thing would be if a person is experiencing... a panic attack now for some people experiencing a panic attack maari po na bumilis naman yung breathing rate nila so ayun po emotions could also affect our starting inspiration now input from receptors causes action potentials that stimulate the respiratory muscles so basically kapag itong mga factors na to blood gas levels movement emotions kapag ito po ay naprocess na medullary respiratory center, it will start sending action potentials to our respiratory muscles.

Second step is the increasing inspiration. Once inspiration begins, more and more neurons are activated. So when our inhale starts, basically, it will encourage other neurons to work.

medullary respiratory center to progressively create a stronger stimulation of the respiratory muscles. Third one is the stopping inspiration. So neurons stimulating the muscles of respiration could also stimulate neurons that are responsible for stopping inspiration.

So again, they're attempting to achieve some form of homeostasis or balance. It's not possible to just continue inhaling a person. They would also do something for stopping inspiration. Inhibitory neurons inhibit respiratory muscles and relax those respiratory muscles. Let's now talk about the factors that affect respiratory rate.

First up, when there is decrease in the partial pressure of oxygen, this would be observed in cases of hypoxia, this causes an increase in respiratory rate. So again, kapag mababa yung partial pressure ng oxygen, our body would attempt to increase this by also increasing the respiratory rate. or yung paghinga ng isang pasyente.

Next, if there is an increase in the partial pressure of carbon dioxide, which is otherwise referred to as hypercapnia, this also causes an increase in the rate and depth of ventilation. Rate and depth. So yung dalas, yung number of inhale-exhale ng isang person per minute, dadami daw po ito. and as well as the depth of ventilation or kung gaano kalalim yung pag-inhale and pag-exhale ng isang pasyente. Again, this happens in cases of hypercapnia or excessive yung partial pressure ng carbon dioxide.

Next, if there is a decrease in the partial pressure of carbon dioxide, this would be referred to as hypocapnia. So this causes a decrease in ventilation. So our breathing rate will slow down because we exhale too much carbon dioxide.

Next, chemoreceptors in the medulla oblongata and the blood vessels near the heart would respond to the changes in the partial pressure of carbon dioxide and also the blood ph all right so let's repeat it located um within our medulla of longata and also located within um the blood vessels near our heart we have chemoreceptors all right so these are um sensory receptors that would detect if there is any change in the partial pressures of carbon dioxide or your ph of our blood because yung increase or decrease ng carbon dioxide in our blood that also affects our affects affects our blood ph all right so these are the factors affecting respiratory rate next we have what is known as the herring brewer reflex so the herring brewer reflex would limit the depth of inhalation preventing the over inflation of the lungs so yung dahilan daw po kung bakit hindi sumosobra yung pag-inflate nung lungs natin. Yung dahilan daw po kung bakit hindi palaging sobrang lalim nung paghinga natin ay dahil sa herring brewer reflex. Again, this would limit the depth or yung lalim ng paghinga natin and also preventing yung overinflation or sobrang pag-expand ng ating lungs.

Again, that is because of the herring brewer. reflex. This slide right here shows us a visual representation of the nervous and chemical mechanisms of breathing.

So again, a lot of these things happen within our medulla oblongata or medullary respiratory center. So pinapakita lang naman po dito yung iba't-ibang mga scenarios and yung iba't-ibang mga organs natin that is involved and that may be able to influence our breathing. If you belong to my lecture classes, that ends our discussion on the respiratory system. Thank you so much for listening. If you belong to my laboratory classes, proceed and go through the microscopic anatomy samples that we may be able to observe with regards to the observation of our respiratory system.

This slide right here shows us a microscopic view of our nasal cavity. So, our nasal cavity itself, these are the spaces we see here, or the white or blank areas. The nasal septum, this is the part that divides, this is what divides between the two external nares, or the two holes in the nose. Other things that we may be able to see here is the oral cavity.

cavity. So right here, ito yung space ng oral cavity and then this organ right here is the tongue. This slide right here shows us three different views of our larynx. Now, if you would remember from the previous discussion, the larynx is otherwise referred to as the voice box, all right?

So ayan po. Kaya dito sa isang view, nakakakita tayo ng false vocal folds. and here are the true vocal cords alright now with regards to viewing these samples in scanner mode it's a bit difficult to actually kind of like identify everything so it makes a bit more sense it makes sense that we are looking at a zoomed in view so for this one we are focused on the low power objective So here at the low power objective, we can see that even from the larynx, we may be able to see that this is already lined with pseudostratified columnar epithelium as we can see right here. And it's also ciliated, right? If you would look at this outer edge right here, right?

So there it is. Again, pseudostratified columnar cells. They're not actually stratified. Mukalang silang multiple layers kasi hindi sila pantay-pantay ng height or hindi magkakapantay yung...

levels or locations of their nucleus. But if you would see the basement membrane right here, all of them are attached to the basement membrane. Right here, we may also be able to observe goblet cells or these white spots right here.

Goblet cells, they may be able to produce mucus. They can secrete mucus. Still on the larynx, ito mga views naman po na ito ay nakafocus na doon sa mismong vocal cords natin.

Alright, so again, our vocal cords, they're capable of producing sound as air passes through them. So when air passes through them, they would vibrate, creating the sound that we are hearing when we speak. Alright, so as you can see right here, kapag may nakikita kayong gandong itsura, this is the vocalis muscle area.

Alright, these areas right here are just ligaments. Next, here's another view showing a tiny segment of the vocalis muscle. And then here outside, we can observe again the usual respiratory epithelium.

Again, what is the component of respiratory epithelium? Pseudo-stratified columnar epithelium. Or let's call it pseudo-stratified ciliated.

columnar epithelium. This slide shows us a sample of the trachea at low power objective. Now again, what is the trachea made of?

It's made of letter C-shaped cartilages, right? C-shaped rings of cartilage. So this is what we see here. Notice this strip of cartilage is lightly curved, right?

So again, on this outer portion right here, we would be able to observe the respiratory epithelium. Again, ano ang composition ng respiratory epithelium? Pseudostratified ciliated columnar cells. These kind of like things right here that look like holes, these are blood vessels, all right?

So these are the blood vessels that would supply oxygen and nutrients to our trachea. And then these areas right here, this is the hyaline cartilage. So don't forget, our trachea is made up of C-shaped rings of hyaline cartilage.

This slide right here shows us an example of the trachea in high power objective. So right here, we're seeing in more detail our hyaline cartilage. And right here, we can see the Pseudostratified Celiated Columnar Epithelium.

Again, these empty spaces or holes right here, these are most likely our blood vessels. Alright, so I guess by now, we should be familiar with the appearance of the Hyaline Cartilage and the Pseudostratified Celiated Columnar Epithelium. Because this is not...

Before we look at it, we've already talked about this when we discussed tissues and histology, right? So here, we're just learning that these two things together, hyaline cartilage and pseudostratified ciliated columnar epithelium, together they would create our trachea. This slide right here shows us an example of the trachea in oil immersion objective view. Okay, so ayan po, dito kitang-kita na talaga natin yung bawat isa dun sa mga pseudo-stratified ciliated columnar epithelium.

And as we can see right here, naka-point out din kung nasan yung area where we would be seeing their cilia or their hair-like structures. Next, since nasa oil immersion objective na tayo, medyo mas nakikita na natin yung connect. tissue components. So these connective tissue components are otherwise referred to as the lamina propia.

Next, again, we saw in the previous slides, these empty spaces right here are most likely blood vessels. This slide right here shows us an example of the bronchial and the alveoli in scanner view. So if, for example, this is the bronchial, And right here is a tiny artery or an arteriole.

It will continue to branch out to the respiratory duct. So when it reaches the respiratory duct, that's where we'll start to see multiple clusters of alveoli. Again, our alveoli is otherwise referred to as air sacs, right?

So there's not a lot of things that we're seeing right here. There's so much empty spaces because these are areas wherein air would pass through. Let's look at this low-power view of the bronchial and alveoli.

So it's the same. The bronchial lumen is usually larger, all right? Mas malaking space. sa gitna ng bronchiol kasi nga, parang it's one of the larger branches. And then after that, it branches off further into the alveoli.

So nakikita natin dito yung simple epithelium and the alveolar air spaces. Right here, we're also seeing an arterial lumen. So usually, magkalapit or magkatabi po yung mga bronchioles and arterioles. This slide right here shows us the bronchial and alveoli in high power objective. So, ayan po.

As you can see right here, if this is the bronchiolumen, alright, this is the bronchiolar epithelium. Now, if we were to compare the bronchiolar epithelium compared sa alveolar epithelium, ayan po, the bronchiolar epithelium is made up of a single layer of cuboidal cells, right? Simple cuboidal epithelium.

Look at these cells right here. They're not squamous, right? They're definitely not columnar.

So they are cuboidal. Pero, yung mga alveoli po, they're made up of simple squamous epithelium. Bakit ganun?

Bakit magkaiba po sila? Because at the alveoli, that's where gas exchange would happen. Di ba po? So it makes sense.

It makes perfect sense na mas sumanipis. yung type of cell na pwede natin makita sa paligid ng mga alveoli in comparison to the bronchiolar epithelium. Right here, it's a bit difficult to see some of the simple squamous epithelium of our alveoli kasi po, we're seeing right here na katabi nila yung capillaries, capillaries, and the alveolar walls, and maraming naka-attach na mga.

RBCs or marami mga RBCs na malapit sa area na to. So parang natatambakan ng mga RBCs yung ibang structures that we're supposed to be observing. But anyway, kapag nakita kayo ng ganito, most likely these are RBCs meaning that capillaries are nearby.

This slide right here shows us an oil immersion objective view of our bronchus. So one of our bronchi. So that's how its composition is. Alright, so it's still composed of that pseudostratified ciliated columnar epithelium. Right here, it points out the specific areas where the cilia is.

And then right here, it also shows a goblet cell. The goblet cell right here is a bit lighter staining. It has a lighter stain compared to all the other cells around it. Again, goblet cells are there to produce mucus. Alright.

Right here is kind of like a layer of connective tissue. And right here, ito po ay yung mga smooth muscles na. Smooth muscles that would surround the bronchus. And again, smooth muscles are there to help us with either bronchodilation or bronchoconstriction. Kapag bronchodilation, mag-i-increase yung diameter ng bronchus.

Kapag bronchoconstriction, mag-i-constrict or liliit. yung diameter ng bronchus, so lilit din yung daanan ng hangin. Again, which medical condition leads to the bronchoconstriction of the terminal bronchioles?

It's asthma. Alright, so pag hinihika yung mga tao, nagkakaroon din sila ng episode of bronchoconstriction. This slide right here shows us an example of the bronchus with cartilage at high power objective. So again, same respiratory epithelium. It's made up of pseudostratified ciliated columnar epithelium.

Guys, if you've seen these things in upcoming practicals and major exams, you'll notice that there's a lot of different types of bronchus. Medyo nakakaya kasi paulit-ulit ko na pong sinasabi ano ang composition ng respiratory epithelium. It's pseudostratified ciliated columnar epithelium. Isa pa, ulitin natin, pseudostratified ciliated columnar epithelium. Pag yan talaga nakalimutan nyo pa ha.

And then right here, we're seeing a bit of cartilage. So again, anong type of cartilage would create? some areas of our respiratory tract.

It's hyaline cartilage. Alright? So, again, ulitin natin yung mga cartilage na pwede nating ma-observe sa ating respiratory tract is made up of hyaline cartilage. This slide right here shows us an example of the alveoli in low power objective.

Okay? So, dito po, ayan, medyo mas nakikita na natin, no, yung simple squamous epithelium, no? Simple squamous epithelium. that would create each of our alveolus or creating all of the alveoli that we're seeing right here. So all of these empty spaces are the air spaces.

This slide right here shows us an example of the alveoli in high power objective with alveolar macrophages. So as we can see right here, there are no macrophages attached to them. ng mga RBCs. So mas nakikita na po natin yung simple squamous epithelium ng alveoli natin.

So these are just a single layer of squamous cells. And again, bakit kailangan single layer of squamous cells lang composition ng alveoli? Because this is where gas exchange would happen.

So we need a kind of like an epithelium where it could facilitate an easy diffusion of oxygen and carbon dioxide. So again, saan gawa? Saan gawa ang alveoli natin?

Sa simple squamous epithelium. And then these ones right here, nakikita natin, these are the alveolar macrophages. So they're present in our alveoli just in case, halimbawa, meron tayong mainhale na infectious pathogens. maybe infectious pathogens out there such as bacteria or fungi, na na-acquire natin sila via inhalation. So minsan, hindi sila natatrap sa hairs ng external nares natin.

Minsan, hindi sila natatrap sa mucous, nakakalusot pa sila sa mucous membranes ng nasal cavity natin. So at least, kapag umabot po sila, kapag umabot sila, sa alveoli natin at least no my next line of defense pataya which is our alveolar macrophages now if you would remember our discussion on the human blood right you mga macrophages but they are phagocytes they are phagocytic cells they are capable of phagocytizing or engulfing you mga foreign substances and infectious microbial pathogens all right so again That's the purpose of the alveolar macrophages being inside of our alveoli. That ends our discussion on the respiratory system.

I am Aurel Enriquez. Thank you so much for listening.

Transcript for:Overview of the Respiratory System

Transcript for:
Overview of the Respiratory System