okay then bring let's bring us to a discussion of the serous membranes let's go to that before we then go forward into the lungs themselves because the serous membrane system is a very interesting system as organs grow like as the harp rose as the long rows they sort of grow into a balloon shaped membrane system like here like the fish going into the bowl because we need to have an ability to separate organs from the muscular and skeletal walls like we need to be able to separate the lungs on the inside from the chest wall on the outside because when we breathe when we move around we want to have the ability to have these organs glide on the inside without having any friction against a chest wall or a nap too involved we have that stuff in the in the in the thoracic cavity as well as in the pelvic cavity I mean that the abdominal cavity in the chest the heart and then the abdomen so these membranes are in the pleural cavity and the pericardial cavity the abdomen area we call that the peritoneal cavity so this membrane since it's originating starts as likely push a fist into a balloon is two membranes that go against one in order one membrane is right around the organ and the other membrane is around the wall like here's the chest wall in our situation and those two membranes on the inside of those two membranes we have epithelial cells and epithelial cells they secrete a fluid it's called to serous fluid since it's the serous membrane system the way we call that and that Floyd lets those two membranes nicely glide past one an order and so that is a really interesting system so it's kind of a closed system it's like it's not two membranes really it's really mom membrane that wraps around the organ first and then around the chest wall but it's fully connected all around and so this serious membrane system is continuous of membranes that are attached here in the text to the body wall and that membrane we call that the parietal part of the membrane or it attaches to the organized that part is called the visual part of the membrane and the epithelial layer on the inside secretes a serous fluid into that cavity that space that's between those two membrane layers and that permits an extensive exchange of movement around those organs without any friction that's a little bit complicated but once you get it is good because in the lungs particularly went along as we call that the pleural membranes so we got a whistle to remember pure and the parietal pleura and inside the lungs inside that pleural cavity we have an assumption that gets created and so that's very interesting because the intrapleural pressure inside that a suction inside there is greater than the suction we get from the atmospheric air so the pressure in atmosphere here is a little bit different and that creates that ability for the lungs to attach to the chest wall and as then the chest wall moves and we breathe in and out the lungs expand with the chest wall and so the lungs in itself don't breathe the lungs are passive they just fill up with air they let go there what actually does the breathing what we call the breathing so to speak is the chest wall that raises when the inhale and that collapse is sort of a little bit when you exhale so the lungs follow the inspiration movement of the thorax if we get an injury and we get a something Stan I can rip that breaks or you know a knife or somewhere its object that we don't like in there but if we get a connection between that intrapleural space that's based between those two membranes and the outside the atmospheric pressure or atmosphere then that's auction gets you know on suctioned and air goes in between and the lungs collapse and we call that a pneumothorax and you see that on this picture right here up here pneumothorax um what we can do there we can we can introduce an object we consumption it back up and we can bring the loan back up because at the moment of the pneumothorax this part of the law is not functioning and that's of course the problem we don't like that so that's that's why the serious membrane system is particularly crucial for all the organs but the long has sort of this double function and that brings us to the lungs the thoracic cavity on each side of the mediastinum that's the middle part of the thoracic cavity where we have to harden is filled with one they are bound below by the diaphragm and they're a PCS there are tips superiorly reach above the first trip so that you got to visualize that that's actually a big deal because you see this here on the picture this is the clavicle this is your collarbone and the ribs I mean the lungs go above the collarbone so when you go above the collarbone and do that divot there and it you know immediately towards to touch the neck you have long going all the way up to their the right lung is divided by two fissures used to write long to fishers a horizontal Fisher and an oblique fissure and that makes it three Lopes a super low amid elope and a nymph Europe allo allo or in general and the last loan because we got the heart there like here is the shade of the heart shape of the heart in here the left only has two lopes you have an upper lobe and lower lobe and we have a oblique fissure only there we don't have horizontal feature just an oblique feature that's fine each slope then is further divided on the insight into pulmonary segments and those are very important landmarks as you see here these collars here these are all the pulmonary segments these are important landmarks for radiology when we want to see what's going on but then also for surgery when we're going to do a procedure we can figure out and identify which pulmonary segment is something in that we don't want or which what do we have to do something with on the mediastinal side that's the medial side that's towards the heart there uninstaller there we have to root of the long and that is a place where we have blood vessels as well as nerves and bronchi enter and exit the lungs that place is called the hilus so the place where the vessels go in and out is the hilus and then we get to delvia and alveoli are the smallest little air sacs here and those are the site of gas exchange and so that's our external respiration that's not the place where the air the oxygen part of the air goes from the atmosphere to the blood system for the external respiration so when we look at that little bit more closely see down here you can see that this is a good picture a team branches of the pulmonary artery so the pulmonary artery is the artery leaving the heart is not enough oxygen in it but it's still in order because it's leaving the heart that falls the pulmonary arteries follow the bronchial tree to the alveoli better network of capillaries facilitates the gas exchange by picking up oxygen and releasing carbon dioxide so these little clingy capillaries here these red bluish things are very closely working together with these grape shaped alveoli and when you cut it you see right in here the air comes in here the oxygen intended from here it goes into the capillaries and then to the heart and then those are then pulmonary veins so these are actually read now because they are carry oxygenated blood back to the heart and then we got a separate network a separate network of lymphatics that drain the lungs it's like everywhere else in every other system where the lymphatics help the drainage and the lowest themselves they also need food they also need oxygen they need energy as well but they get supplied by a separate vascular network not by this vascular network that's the same thing with the heart you're going to have the organ itself not get fed with a different vascularity then then what's the transport of the blood itself oh cool little fast not that fast not that fast ventilation of the long so now we have a rhythmic breathing allows oxygen rich fresh air to reached LVL I an option poor which is carbon dioxide rich you know we come to these rural place and sometimes to do that but we have this oxygen poor air leave your viola breathing is accomplished when the lungs follow the movement of the thorax so we already talked about that before and that's due to the intrapleural pressure that's the reason why the lungs can be attached and suctioned to the thoracic wall and then follow the movement of the muscle of that wall and when we do that movement actually the most important muscle is actually the diaphragm the diaphragm increases the chest cavity volume by moving downward by moving inferiorly and then the autumn also that work together with that is the external intercostals which are the ones here between the ribs on the outside and they actively elevate the thorax and then do changing the lungs volume changes the intrapulmonary pressure in relationship to the Atmos furyk pressure and in this way this is a complicated way of explaining how air is sucked into the lungs during inspiration than expelled during expiration so the intrapulmonary pressure this were down here intrapulmonary pressure that refers not to that intrapleural pressure that was in between those membranes this is now the pressure on the inside of the lungs and for a brief moment if you keep if you will keep your mouth closed and you don't close to do it expand the chest wall that inside the lungs pressure is below the one on the outside and if soon as you open those passageways which they're always open Oh click that air just Falls impassively because it wants to flow from a higher pressure area to a lower pressure area again with passive movement it always wants to go from a higher something concentration something to a lower concentration of something so that's what you have right there that's a complicated way of explaining that if you need to bring the air in if you need a force exploration we have excessive breathing muscles that further increase the chest volume so we get these muscles rpm for example we get the neck muscles that lift up the chest a little bit more and I bring it up we can even bring the arms out a little bit more expanded laterally a bit more when the X prior we simply relax the diaphragm and the chest wall returns mostly through passive recoil to the resting position we can forcefully expire and we ate that by compressing the ribcage further because we got internal intercostals that pushed the ribcage downward but we also can compress the abdominal content and further decrease that chest wall adp anterior posterior so we can do that