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