I engine NDS in this video we're going to go over the hemoglobin oxygen disassociation curve so this is just going to be a nice little way of recapping everything we talked about an internal and external respiration but seeing it in more graphical representation okay so when we look here we're going to have a y axis and an x-axis on the Y AIS this is going to be representing the percent Satur ation of the hemoglobin now when we talk about percent saturation what what do we mean by percent saturated it's how much oxygen the percentage of oxygen that's bound to hemoglobin so that's what percent saturation means so the percent and I'm going to put sat the percent saturation oh I wrote that again double percent saturation of hemoglobin okay HB and again what is this percent saturation of hemoglobin mean it means it's the amount of oxygen that's bound to hemoglobin in percent form that's it so now that's the Y AIS on the x axis we're going to have the partial pressure of oxygen particularly uh we're going to use it in millimeters of mercury okay so now we have xaxis partial pressure of oxygen millimeters of mercury on the y axis we have percent saturation of hemoglobin good that's good now what do we see in this curve we see this curve look at this when we start over here at about let's say that we come over here to about 104 I'm going to start moving moving as the partial pressure of oxygen is decreasing look what happens it's the partial pressure of oxygen is decreasing it's kind of staying the same nothing's really changing nothing's really changing oh but it starts to go down down down down down down down down down and it makes kind of like a s shaped when it makes some somewh this s shaped that's a specific type of curve so that curve is called a sigmoidal curve so this curve is specifically called a Sig midal curve so this is a sigmoidal curve it's kind of like an s-shaped curv and what it's trying to represent is that this is kind of the plateau pH so no matter how much more oxygen you add on no matter what it's not going to change the percent saturation of hemoglobin so for example just for example it doesn't have to be perfect but if we come up here to about 60 and we go from 60 all the way here to about 110 no matter how much more oxygen I have it's not going to change the percent saturation of hemoglobin it's still going to remain at about 98% saturated okay but as we go over here maybe about 50 all the way down here to about 10 as I start moving my way down and this partial pressure of oxygen starts decreasing then the percent saturation starts decreasing significantly and we're going to explain what's happening so now what is the normal so we're going to take this black line here this is representing ing the black line is representing normal situations no no changes nothing abnormal we'll talk about the the changes in the pink and the orange but first let's focus on the black one which is just normal in normal physiological conditions what is the partial pressure of oxygen in the lungs and in the systemic arterial blood you know that that's right around here so look it's about right there CU you know you have 100 110 right in between there is about 104 that's the number we want let's write that down then so right here about that point right there I should have 104 millim of mercury and where should this be this should be in the lungs so if this is in the lungs let's follow this up to that black line now okay so we follow this up in this black line let's do this in this nice blue I'm going to come up here I'm going to move up and I'm going to move this way now so now look I'm going to come over this way we're going to get it to about right there not perfect you know not a perfect line here but I just want you guys to get the point here if I come down here to about that point so it's going to fall right in between this now technically if we were to be really really specific it should fall uh right in around 98% obviously it looks looks like a half 95 but in the lungs it should be 97 98% saturated okay so this is going to be where this is in the lungs okay so let's write that right over here so this is going to be in the lungs now what happens is after you have this gas exchange that occurs in the lungs right so you know there's gas exchange in the lungs and that's where the actual the actual oxygen is moving right so the partial pressure of oxygen the alveoli is 104 millim of mercury it'll move from the alveoli into the pulmonary capillary blood until the pulmonary capillary blood has a partial pressure of oxygen that's about 104 mm of mercury then it'll go to the systemic arterial blood when it goes to the systemic arterial blood it'll again then get trans ported to our tissues you know what the normal partial pressure of oxygen is of our resting tissues it's generally around 40 mm of mercury so here at about 40 millimeters of mercury this is the point in which our tissues so this is the point in which our tissues are at rest okay so it's usually the resting point for our tissues so this is the resting point of my tissues let's see what the big difference is between 104 mm of mercury so the partial pressure of oxygen at 104 millim of mercury which is in the lungs in the systemic arterial blood versus the partial pressure of oxygen in our tissue cells so the muscle tissue so now let's follow this bad boy up so if I follow this bad boy up here I come up to this point here and I move over nice right there at about where it's supposed to be around 75% so this is usually the partial pressure of oxygen in the actual uh specifically after gas exchange has occurred so because watch this this if I come up here what did I tell you this is the partial pressure of oxygen where in two places it's the partial pressure of oxygen in the lungs because that's where the gas exchange is occurring oxygen is moving from the lungs into the blood the other part where it's 104 millimeters of mercury is the systemic arterial blood then the systemic arterial blood is taking the oxygen taking it in the form of the blood to the tissue cells and dropping that oxygen off to the tissue cells the normal partial pressure of oxygen in the tissues is 40 mm of mercury now after the gas exchange occurs after the oxygen has been dropped off to the tissues we see that the the actual percent saturation of hemoglobin is 75% but that 75% is no longer in the arterial blood that 75% there right there is specifically this 75% saturated hemoglobin is for the venous blood but even more specifically for the systemic or peripheral venous blood okay so now what am I trying to tell you here let's say I utilize this a calculation so at 104 millim of mercury which is the systemic arterial blood's partial pressure of oxygen the percent saturation of hemoglobin is 98% okay cool let me utilize that number then so 98% saturation of hemoglobin in what and I'm going to put AB for the arterial blood okay this is for the arterial blood I'm going to subtract that from the saturation of hemoglobin after the gas exchange has occurred in the Venus blood so now this is the mixed venous blood right this is approximately 75% after the gas exchange occurs at the tissues so this is at 75% saturation of hemoglobin but this is specifically after the gas exchange has occurred so now this is in the Venice blood what do I mean here let me let me let me give you guys a little diagram uh diagram let's say here I have a capillary which goes to a tissue cell and you know that the capillaries will feed into this tissue cell and you know you'll have your arterial you'll have your capillary bed and then you'll have your venal and you know over here you're going to have your tissue cells so let's say here I have a couple tissue cells what do we say was happening in the internal respiration we said oxygen was moving where we said oxygen was coming from the hemoglobin so let's say this is the oxyhemoglobin what was he doing he was dropping off oxygen to the tissues as he was dropping off oxygen to the tissues the tissues were producing CO2 and what was happening the CO2 was binding onto the hemoglobin and causing oxygen to be letting go of the uh the I'm sorry letting having the hemoglobin let go of the oxygen what was the percent saturation of that hemoglobin at that point right before he starts dropping off the oxygen it's approximately 98% but then when it dra RS out of the capillary bed what is the uh concentration of the hemoglobin afterwards so I'm going to put deoxyhemoglobin we have a very little oxygen but this is deoxy so if this is uh if this is oxy guys what would this be R state if this is deoxy this is t-state okay what would the uh hemoglobin saturation be after it's drained from the capillary beds well if we assume that the partial pressure of oxygen here in the tissues the muscle tissues for example is 40 mm of mercury well then we said the percent saturation at that point in time leaving should be 75% now the question is when I subtract these two when I take the difference between these two what am I actually obtaining well I'm obtaining how much oxygen was being unloaded to the tissue cells that's it so I'm actually calculating the percent oxygen being unloaded so if I do the difference here 8 - 5 is 3 9 - 7 is two that's going to be approximately 23% percent of what of oxygen unloaded sweet deal that's a cool thing now let me do something different let's say I take for example a tissue the same tissue it was originally at rest and now let's say that I amp its metabolic rate up and what would cause that exercise let's just say for example I'm exercising and I'm going ham I'm going to hit biceps and triceps today I'm going to get those you know I'm going to get that nice little tricep all right I don't have any anyway we're coming back here and look what happens he starts exercising this individual starts exercising and look what happens to the partial pressure of oxygen it goes from 40 and let's say that he's working out hard and it drops down to about 20 so say it goes from 40 to 20 so let's say at this point here we're taking the tissues the partial pressure of oxygen of the tissues but specifically during vigorous exercise so let's say that this person is exercising exercising really really hard they're hitting the glamour muscles they're hitting the triceps and the biceps today all right now if that's the ca if that's the case and they're utilizing so much oxygen so what do I mean by they they're utilizing a lot of oxygen let's say for example I take this tissue cell if its metabolic rate is increasing it's going to want to utilize more oxygen so it's going to produce more CO2 right which is going to cause more oxygen to be unloaded as it produces more CO2 and more protons you guys remember from the internal respiration video that that caused that bore effect it weakened the bond between oxygen and hemoglobin and oxygen was let go well the more CO2 you produce the more H+ you produce what was the other molecule the more 2 comma 3 BPG you produce and what else the more higher the temperature this is going to weaken that bomb between the oxygen and the hemoglobin it's going to let go of more oxygen the more oxygen you let go of that tissue cell is going to continue to keep metabolizing it and utilizing it to make energy now let's follow this bad boy up and see where he goes so I come here at 20 and look what happens here holy moly that is a huge difference I went from 75% all the way down to 30% now obviously this isn't perfect but you guys get the Point obviously this wouldn't be as significant it might drop down to about 55% but if we go to 20 and we move our way up move over oh wow 30% let's do that calculation so let's say we take the situation here now don't don't worry about this one anymore we're not going to compare this one for right now we're still going to look at the systemic arterial blood and we're going to look at the actual changes when it's at 20 millimet of mercury and we'll compare it to the resting tissue okay so don't worry about this for right now let's only focus on this one so let's come over here and do that so say for example I start off with again my 98% and that 98% is for what again guys it's the 98% saturation of hemoglobin but where in the arterial blood good now we're going to subtract the difference between what at 20 millimeters of mercury when our our tissues enter in vigorous exercise we go up boom 30% still blows my mind but that's just the graphical representation of it here 30 percent percent what saturation of hemoglobin but where in the venous blood and again what did I mean by that again take that example here's my capillary I might be beating a dead horse but I just want you guys to really get the point here let's say here's my tissue cell and if here's my tissue cells and again what's happening to these tissue cells they're taking up a lot of oxygen and why are they taking up a lot of oxygen because they're producing massive amounts of CO2 they're producing massive amounts of protons they're producing massive amounts of 2 comma 3 BPG they're producing uh lots of temperature in the form of thermal energy and what is that doing to the hemoglobin it's decreasing the affinity for oxygen so where's oxygen going to go it's going to disassociate and it's going to go to the tissues and it's going to go to the tissues enough to where these tissues can utilize that oxygen to produce massive amounts of ATP why did why do muscles need ATP to to contract so that's why this is happening now let's take and do the difference now so now if I take 98% and I subtract 30% what is that going to be well this is going to give me 8 and this is going to give me 68% but 68% what oxygen unloaded to the tissues that's a lot okay so if we compare if we compare this right here 68% of oxygen unloaded but when let's even be more specific during exercise versus over here 33% of the oxygen that's unloaded When what when we're resting chilling out watching Breaking Bad or the new prison break love that you're just killing eating some potato chips and what is that percentage of oxygen going to be unloaded 23% but this is just that rest that's a significant difference if we compare the difference between these two that's a huge difference 68% and 23% that's a huge difference what's the overall concept here here's what it is now we're going to talk about this pink line and this orange line here okay so here's what you're notice you probably have noticed here you've seen a shift right a little bit of a shift here's our normal right and I told you that we would talk about this pink one we talk about this orange one well you'll notice here a shift this way and you'll notice that this line shifts this way okay let's talk about the one that's shifting towards the right what do I notice right away let's compare here at resting tissue the normal versus the resting tissue in this pink line okay well at resting tissue what do we know was the actual percent here was 23% let's bring that over there so it was 23% oxygen unloaded at rest in normal scenarios okay so I'm just going to put situations here okay now let's take for example what it would be if we utilize this same thing here but we stop right there now they're not going to this black line we're going to that part of the pink line where it crosses and now let's move over with that so if we come right here to this point where it intercepts and we move over takes it to about 60% about so now do that calculation if we do that calculation and again it starts with 98% saturated hemoglobin always 98% saturation of hemoglobin in what the arterial blood and we take the difference of the percent saturation of hemoglobin when it was actually with this pink curve which we haven't talked about yet and it was about 60% so let's take with sub difference of 60% saturation of hemoglobin but this is is after gas exchange which means it's in the ven venous blood the mixed venous blood if that's the case then what's the difference going to be this is going to be approximately 8 minus this is 8 and then this is 38% so 38% oxygen unloaded okay at this resting point at this resting point in let's say for this case the pink curve okay what's the difference then more oxygen was unloaded in that pink curve if we compare here this is our pink curve here and this is the one that was actually in the black curve there was a lot more oxygen unloaded to the tissue cells whenever it was in this curve because it's shifting to the right what could that be due to you know what it's due to if you guys remember the bore effect this is due to the bore effect so the bore effect is due to a shift right they call it right so it's shifting to the right of the curve and what does that mean that means then there has to be some situation that's causing more oxygen to be unloaded at the same partial pressure of oxygen when it's at normal versus some other condition what is that condition that is when there's a lot of protons so your body's producing a lot of protons right your actual cells are producing a lot of CO2 there's actually going to be a lot of 2 comma 3 BPG BOS bis phosphoglycerate right I'm sorry bif phosphoglycerate and there's also going to be an increase in temperature in these situations in which there is a decreased affinity for oxygen who for from hemoglobin right so hemoglobin's affinity for oxygen is going to decrease what's the overall situation there's going to be a lot more oxygen leaving the hemoglobin and going into the issues that's the concept with this curve so this curve is supposed to represent the bore effect and all the bore effect is representing is a shift right from the normal curve and it's indicating that at the same you take the normal curve at 40 millimet of mercury the percent saturation is 75 you take that that same partial pressure of 40 millimeters of mercury in this bore effect curve it's at 60 and that's due to more protons more CO2 more 23 BPG more temperature all of these things are going to weaken the bond between o oygen and hemoglobin which is going to cause more disassociation so what's the overall effect of this increased oxygen dissociation okay that's the whole concept of the bore effect now let's look to this situation in which there is a shift left so now let's take the scenario in which this actual curve is Shifting to the left now so now this curve is Shifting to left if we take this situation here and we compare it now so let's go for 40 mm of mercury to this guy 40 mm of mercury to the normal one let's go up one more and follow it over okay and then boom 85% okay so this point here it's at about 85% let's do that math one more time and then we're going to compare this and finish up the video okay so again normal saturation of hemoglobin is 98% in the arterial blood so let's keep going off with that one so 98% saturation hemoglobin and arterial blood AB right now we're subtracting the difference between the saturation of hemoglobin which is approximately 85% saturation of hemoglobin and the venous blood in other words after the gas exchange occurs we're going to take the difference between these two if we take the difference between these two again what do you get you're going to get three 133% uh 133% what 133% of the oxygen is unloaded into the tissues so there's 13% of the oxygen unloaded to the tissues that's not as much oxygen as normal so 133% oxygen is unloaded to the tissues so what is causing this situation where oxygen doesn't want to leave well it must be some situation in which there's a high Affinity that hemoglobin has for oxygen so wouldn't that be the exact opposite of this yeah that's what it is you know what they call that they call that the howan effect so they call this scenario the howan effect and you guys remember this we talked about an external and internal respiration what's the overall concept then it's just going to take the exact opposite so now if it's the exact opposite let's say here for the howan effect we're going to want to have low CO2 presence right we're going to have low presence of protons we're going to have what very little 2 three BPG it's going to be cold as ever decreased temperature and what's going to happen to the oxygen presence the oxygen presence is going to be very very high so there must be a lot of oxygen here if there is a lot of oxygen so in other words in the howan effect because there's decreased CO2 decreas protons decreased 2 comma 3 BPG decreased temperature the hemoglobin affinity for oxygen must be high higher so what does that mean then if hemoglobin wants to hold on to the oxygen it's not going to want to dissociate as much so the whole effect of this is there will be a decrease oxygen dissociation that's the overall effect of this okay so in this video we talked a lot about a lot of different things okay we went over a lot of this with the graphical representation of the bore effect the howan effect and the normal external and internal respiration doing a lot of boring math but I hope it made sense guys I really hope you guys did enjoy it if you guys did please hit the like button subscribe put a comment down in the comment section all right guys until next time Ninja nerds