of a rubber band so that's going to be the major force in terms of breathing out but if um again you have forced exhalation then you're going to be using your internal intercostal muscles as well as your abdominal muscle muscles your rectus abdominis and your obliques and okay so this is showing the different the different muscles that are used for inhalation and exhalation all right so i like this guy because this is pretty much showing you what i drew on the picture it looked much much nicer atmospheric pressure 760 millimeters of mercury um normal quiet breathing diaphragm external intercostals contract and um the thoracic cavity increases in size volume the lungs expands and the pressure drops to 758 and air rushes in normal quiet exhalation the diaphragm and external incostals relax and you have that elastic recoil occur the diaphragm rounds back up again and the alveolar pressure increases because the size has gotten smaller to 762 millimeters mercury and air moves out okay um i didn't talk about surfactant so there's a thin layer of food in the alveoli that's that's released by the type 2 alveolar cells and we know that water forms hydrogen bonds with other water molecules and that creates high surface tension so the type 2 alveolar cells are going to release a detergent like substance called surfactant and what surfactant does is it decreases surface tension of the water that moistens the inside of the alveoli so that basically if you don't have surfactant what would happen is when you exhale it'd be fine when you inhale when you exhale the alveoli would collapse because of the high surface tension it would cause them to collapse and then when you inhale you'd have to inhale with enough force to open up all of those alveoli and it would really suck up all your energy it would be hard to keep up with you wouldn't be getting enough oxygen in all of those occur now in premature babies two of the last things to completely develop are the lungs and the eyes and so oftentimes you see they'll have vision problems as well as respiratory problems and the respiratory problems generally come from lack of surfactant so that's called respiratory distress syndrome okay and that is going to cause the alveoli to collapse every time you exhale all right now compliance has to do with the elasticity of the lungs so it's the ease with which it expands and that elasticity is also going to be the major driving force of exhalation so certain diseases reduce the compliance anytime you have scar tissue remember it doesn't function like normal tissue so scar tissue is always going to decrease compliance if you have paralysis if you have edema anytime you have edema in the lungs the surfactant is diluted and now you're going to have a problem because remember the surface tension increases those alveoli are going to collapse because of the high surface tension and so anytime and so like with pneumonia with pneumonia um you may have an infection or something and inside your alveoli um you may have immune system cells trying to fight off the infection and you're building up fluid inside there as the fluid increases you're diluting the surfactant it's going to become harder and harder to breathe so anytime you have any type of fluid in your lungs it's going to affect your ability to breathe because of dilution of surfactant your airway resistance when we talked about resistance in the blood vessels we talked about the mainly the pressure of the blood moving through the blood vessel that friction caused resistance and also the viscosity of the blood and the length of the blood vessels but with the airway it's strictly related to the diameter of the airwaves so if the something happens to compromise the diameter of the airways like if you have an asthma attack or anaphylaxis or something like that it's going to cause them to decrease in diameter you're going to have more resistance and it's going to be harder to breathe all right so we talk about breathing patterns eugenia it's normal breathing apnea is breath holding you probably if you've heard of apnea you've heard of it in terms of sleep apnea and sleep apnea occurs generally because the tissue in the back of the throat in the back of the mouth at the the entrance to the throat collapses over the opening and um the person stops breathing if you ever saw anybody with sleep apnea try to breathe you can see that you know it's like like that while they're sleeping um struggling to breathe um and so they actually wake up generally not consciously wake up but their system wakes up because they may stop breathing several times a minute and so it can be treated with surgery to remove that tissue sometimes if people are obese they have sleep apnea and they lose weight then they don't anymore also they use cpap machines that puts air under pressure and that helps to keep the airway open okay sleep apnea puts a lot of stress on your heart so it is a dangerous condition dyspnea refers to painful or difficult breathing tachypnea just like tachycardia together it's rapid breathing costal breathing means that you're going to be um it's usually we use that term in terms of the way you breathe when you exercise because remember you're going to use your internal external intercostal muscles for increased ventilation during exercise diaphragmatic breathing is the way we breathe all the time and then modified respiratory movements are used for things like coughing and hiccuping and stuff like that all right so let's take a look at lung volumes now i said you don't have to know this chart for the lab portion but i could ask you questions about it one thing i'm not going to ask you is about the different volumes like how much volume is the inspiratory reserve or something like that but it's a good idea to know what these different guys are okay so your normal breathing in and out in and out in and out is your tidal volume and it's about a half a liter at rest normal breathing in and out if you've ever had a breathing test um you may have used a spirometer if you've ever had surgery and you have to breathe into a spirometer before you leave so they know that you can breathe properly um a handheld spirometer if you ever had a breathing test it's a lot different than breathing through a handheld spirometer you actually go into like a little booth and they hook you up and then you have a bunch of technicians yelling at you no breathe harder breathe harder but what you do is so it moves in this direction it moves from left to right so here's where the record starts this is a spirogram here which is a or spirograph which is a record of a breathing test so here's your normal breathing and then they say take the deepest breath that you can possibly take and you do inhale as much as you can possibly get into your lungs and then they'll say exhale exhale exhale exhale and you try to exhale as much as you possibly can all right and from this they can get a lot of information first of all you have your title volume your inspiratory reserve volume is whatever you can inhale above that tidal volume okay so here it's 3100 mils if you um add this to it you get your total inspiratory capacity with these 3 600. now the amount of air that you can exhale below the tidal volume is your expiratory reserve volume okay if we add the inspiratory reserve volume the title volume and the expiratory reserve volume together so basically we're saying what is the maximum you can inhale and what is the maximum you can exhale uh pulmonary function tests um i'm not sure if they call this a pulmonary function test they may um i'm not sure what the exact name of it is in a clinical setting but that sounds like it would be right so the maximum you can inhale plus the maximum you can exhale is called your vital capacity and this is one of the main measures of lung how well your lungs work okay your vital capacity is basically what you look at and your vital capacity for most of you is never going to be higher than it is now because usually people's vital capacity is highest when they're in their early 20s which is where a lot of you not all of you but a lot of you are from there it's all downhill my friend and guys have a higher vital capacity than girls do they have bigger lungs okay so uh the person who would have the highest vital capacity would be like a man who's in his 20s early 20s so if you're an athlete you may have a higher vital capacity if you have any sort of lung issue like asthma bronchitis if you smoke smoking's big decrease of your vital capacity um any of those things and age decreases your vital capacity as you get older your vital capacity gets smaller and smaller okay so of all of us i have the smallest vital capacity not only am i a girl but i'm older than all of you so my vital capacity would be the lowest in the class okay so that's a measure of lung health your vital capacity now if we add to that residual volume that gives us the total lung capacity so what the re residual volume is is it happens when you take your first breath very first breath when you're born you're going to get some air that's going to go into your your tubes and your lungs that's going to permanently stay in there not the exact same air but you're going to have a certain volume of air that's always going to be in your lungs to help keep everything open and that's called the residual volume and is permanently trapped in the system you add that to the vital capacity and you have your total lung capacity okay so we looked at dalton's law right and then henry's law nitrogen narcosis and decompression sickness um so the hyperbaric oxygenation used to teach an it can also be used for heart disorders carbon monoxide poisoning cerebral edema bone infection gas embolism and crush injuries is point three okay in the alveolus it's hard to be able to share your screen sorry oh geez you scared me yes i'm sorry let me do that i startled very easily okay sorry i didn't lose no that's all right that's all right it just happens it can't help it so the partial pressure of oxygen in the atmosphere is 159 millimeters mercury co2 is 0.3 in the alveolus it is 105 for oxygen okay and carbon dioxide's 40. in the capillaries carbon dioxide's 45 oxygen is 40. okay so and this is the one coming away from the tissues and then the one going towards the tissues it's 140. okay