Oxygen-Hemoglobin Dissociation Curve

this whiteboard tutorial is going to go through the oxygen hemoglobin dissociation or saturation curve so we're gonna be zooming in and out of hair so bear with me as we kind of zoom in to look at our little red blood cell so before we get into our saturation we have to understand what's going on with this red blood cell so remember that our typical red blood cell biconcave desk has no nucleus which is and can cause problems the question is how does it do work how does it get energy so we're going to talk about it first and foremost as being a sack of protein and you say okay well what's that protein we talked about hemoglobin right and we'll say that we have hemoglobin as a protein filling this sack and we say well how much hemoglobin and we tend to say that four oxygens bind to hemoglobin people just make that direct assumption that every red blood cell has one hemoglobin that binds for oxygen and we're good to go when in actuality we get per red blood cell roughly 270 million mmm hemoglobin molecules within each red blood cell again that's an average so then we go to our red blood cell and say well how does this this guy this thing do work well how does it get energy well we work through a process of glycolysis okay glycolysis and what this pretty much does is it takes glucose and it's gonna convert it to pyruvate and what this is gonna do is it's gonna give us the ATP we need in order for this cell to do work now we're gonna come back to this a little later because there is a byproduct of this right here that we are gonna have to talk about that does affect the oxygen saturation our next step in this process is to look at actual hemoglobin if we go back to our red blood cell that we talked about back when we did blood we remember that hemoglobin has four subunits and alpha 1 and alpha 2 a beta 1 and a beta 2 so we're not going to get too crazy with that right now but we do want to talk about how oxygen is going to bind to this hemoglobin so we have an oxygen molecule that comes in and it's gonna bind to our first hemoglobin and what this does is it's going to cause an increase so we're gonna change this to red and we're gonna cause an increase in the affinity of oxygen to its neighboring subunit so now oxygen is going to bind to the next one and it's going to increase the affinity of these subunits and then we see this cascading effect and then we get once oxygen binds to our second subunit we get an increase in affinity for the third subunit to bind and here comes oxygen binding even more affinity to that third subunit even stronger connection and so forth we go to an increase in affinity and the fourth subunit and oxygen is going to go and increase the affinity to bind oxygen to that fourth subunit this is called cooperativity so what happens is these guys are cooperating tivity they're cooperating with each other to bind more strongly each successive time for each subunit so that allosteric binding so in chemistry we call allosteric binding the allosteric binding of oxygen is going to increase as the subunits cooperatively work together so from here now we can make our board a little bit bigger so put our hemoglobin out into the corner and we're gonna draw ourself a saturation curve and we'll call it our oxygen hemoglobin the association association curve so now we can start labeling our axes and putting in some number so we're gonna put a zero here we're gonna call this side our percent saturation of hemoglobin and we're gonna call our x-axis our partial pressure of oxygen and we're gonna put it in millimeters of mercury now we can start putting some numbers here let's mark this is 10 20 30 40 50 60 70 80 90 a hundred and we're gonna go half to a hundred and five remember that we said the partial pressure at the lungs is a hundred and five millimeters of mercury then we're going to go up our y-axis and we're going to do the same thing 10 20 30 40 50 60 70 80 90 and 100 now let's draw our sigmoid shape curve so we're gonna start at 105 and we're gonna try to maintain this curve I'm gonna come straight down into zero so let's explain what's going on here let's go up to 105 and we're gonna drop a dashed line down to 105 and we're going to see that we have 98.5 percent saturation at the lung so we're gonna change colors and we're going to do this and we're gonna bracket a couple of regions and we're going to explain what's going on here so our first bracketed region is what's going on at the lungs and systemic blood vessels Oris okay and then this second dashed line is going to be what's happening at a tissue level okay so let's go we're gonna switch again to red so that we can understand what's going on here so remember that hemoglobin and oxygen are going to bind they're gonna bind specific pressures we could put an analogy we think about a magnet take two magnets and then take the positive end of both magnets and try to push them together you'll feel that they push apart so the question is well how do you get those two magnets that technically don't want to stick to each other to touch and the answer is well pressure you can apply a specific amount of pressure to get those ends of those magnets to touch oxygen and hemoglobin are no different oxygen human will technically do not like each other they're going to repulse each other but if you apply a specific amount of pressure specifically here a hundred and five millimeters of mercury we will get 98.5 percent of oxygen binding to hemoglobin now we have a range so this green range that we just outlined is going to be so right here is going to be the saturation at the lungs and then as it carries those systemic arteries and this is good because look as we travel down this line right and we're in those arteries the partial pressure is decreasing as we expect it to until we get to the tissues but the way the affinity for oxygen the way that oxygen is binding to hemoglobin isn't changing we're staying right at about ninety eight point five percent and this is good because this is what we want and this is what we expect if you go back to what we just said we said that oxygen is going to by ninety eight point five percent of it is going to bind at the lung level right so we're loading oxygen at the lungs and then at the tissues we have to get rid of it we have to unload it so how do we do it with pressure so now we can go back and like Penn marker and we go back to our tissue level now remember in our tissue level we were at 40 millimeters of mercury and we follow this all the way up our chart and we see sorry that line is not that straight and we see that we are about 75% and that's what we expect right so at the tissue pressure drops to 40 millimeters of mercury and we follow our chart and we see that 75% is now bound so what happened right what happened to the oxygen what happened to the affinity of oxygen for hemoglobin so now we can say what's happening we're gonna put some numbers to this and we're going to look at an arterial end and a venous and so if we look at Anna Tyrael end right by the time we get to the tissues we have 98% of hemoglobin is bound okay so then what happens pressure decreased decreases to 40 we get 75% of oxygen is still bound to hemoglobin so what happens so we get a net so we say 75% of hemoglobin is bound this is going to be arterial and this is going to be venous end so what happened to that 23 percent so we do a quick math problem we subtract 98 from 75 and we see that 23 percent of that oxygen that was bound to hemoglobin in the arteries was released into the tissues okay now again we're naming this as being normal this is you just sitting still not really doing anything this is our normal saturation curve okay so we'll just recap and we say okay well just sitting here doing really much of nothing and everything temperature and everything being constant we see that our lungs is doing its job we're loading up ox 98.5% as we travel through those systemic arteries we now drop the pressure in the tissues to 40 and percent saturation went to 75 so now what happened to the affinity for oxygen as pressure decreases pressure decreases we went from 105 to 40 millimeters of mercury the affinity for oxygen went down okay the affinity went down which means that we started letting up on the pressure on back to our analogy the magnet and they started pushing apart so again misconception people think that we load up on two percent of oxygen that the lungs that we deliver a hundred percent at the tissues this is not the case we are only losing roughly 23 percent now this curve is dynamic it changes every second of every day with a few factors so what we're gonna do is we're going to shrink our chart down we're gonna make our whiteboard a little bit bigger and we're going to look at some factors that affect this normal dissociation curve now we're going to talk about things that's going to affect this curve so we're going to kind of slowly erase some of the things we wrote and introduce some new lines here more precise okay now we have our chart back let's get our line back so let's see what effects this curve so things that can affect this curve we're gonna use this pneumonic so we're gonna shift this curve right and we're gonna shift it left so we'll see what effects the shift right there no Manik we're going to use is cadet face right okay so if you think about the military when you have soldiers and training they're called cadet and when they are made to stand in line they face right so a right shift curve follows the mnemonic cadet so we think about things that will start with this letter so first is going to be for carbon dioxide the a is gonna stand for acidity the D is gonna stand for 2-3 BPG so-die phosphoglycerate or 2 3 2 3 bisphosphoglycerate we'll talk about what that is in a second the EES gotta stand for exercise and the T is gonna stand for temperature okay now what happens to a shift right let's use a red line to draw a curve shifting right so we have a rightward shift now what causes that shift right and we'll make this red arrow here is going to be an increase in co2 an increase in acidity an increase and 2 3 bisphosphoglycerate which is seen elevated in pregnancy and this makes sense because those red blood cells are going to be doing more work and before when we talked about that byproduct and we're gonna zoom on in right here we talked about that by-product that we were going to talk about later of glycolysis well here it is and the byproduct that we are going to be talking about is 2/3 B P G no I'm gonna zoom back out and kind of move back over to our shift and we'll say ok well an increase an exercise and an increase and temperature and all this makes sense right and we'll get into that carbon dioxide oxygen shifting in the red blood cell but as you exercise you be coming to an oxygen debt and that you have to repay that oxygen debted miss and we know from what we said before that hydrogen ions start popping off as you're moving more co2 so co2 increases because those hydrogen ions are filling that plasma in that blood we get an increase of a city because the red blood cells are doing more work we get an increase in to 3 BPG and again goes with exercise in our body temperature will increase so let look at our saturation or percent saturation how does this affect the curve so we look over here and we say okay at a tissue level and we follow it up we follow it up and we say good nothing is changing not at all so we get 98.5 percent saturation at the tissue level and this is good this is what we want so we're breathing in and we're binding 90.5 all the oxygen that we could bind to even globin is binding where is the change let's follow our tissue level up we go to 40 big change we are now getting 50 percent saturation so what does that mean let's go back to our calculations and we say ok on the arteriole end we are binding 98 well make this a little smaller so we have a little more room we're binding 98% so at 105 millimeters of mercury through arteries on our lungs and our systemic arteries were 98 percent bound a FEMA globulin of hemoglobin bound by oxygen now as we decrease down to 40 millimeters of mercury what happened in our venous so this is again arterial end and our venous end we are decreasing to about 50 percent of saturation so what happened here if we do a quick math problem like we did before 98 minus 50 is 48 so we are getting 40% of that available oxygen delivered to the tissues and this is smart so if we zoom back out and go back to things that are causing this exercise is causing a shift right increase in temperature shift right on a really hot day when you're sweating your oxygen saturation curve is going to shift right again dynamic these are things that are happening all day long Oh to co2 is increasing acidity is also creasing so what do we do we have to repay that oxygen debted miss this curve has to be dynamic we have to be able to adjust the rate of release of oxygen to the tissue and we did 48 percent we doubled more than double the amount of oxygen being delivered to the tissue with a shift right so think about that in a common-sense way this is what we expect we're entering to the oxygen debt the pressures were meaning the same we cannot affect we cannot change the pressure in our body but we what we can change is how tightly how strongly how the affinity for oxygen the affinity for oxygen to hemoglobin we could affect that so by shifting this curve to the right we decrease the affinity of hemoglobin to oxygen so while we get to 40 millimeters of mercury more oxygen is being delivered to our tissues now we're going to take this and we're going to move this out of the way so that we can so let's go ahead and now let's erase to write for shift left okay now let's go back to our pencil let's change our color now we're going to shift this curve to the left so let's zoom in we're gonna draw a curve follow our same line and now we shift left now what does this mean what's happening here so it's gonna be the opposite co2 is going to decrease acidity is going to decrease to 3d PG is not really a factor here but exercise will decrease temperature decrease when can this happen if you are sitting in a lecture room that is is extremely cold and your temperature goes down your oxygen saturation curve is going to shift left then we'll see what that means that a percent saturation how that affects percent saturation our co2 is going to go down because we're not exercising the levels of co2 is not increasing respiratory rate is not increasing which means acidity is now going to go down because our cells are red blood cells are well oxygenated okay and we're at rest sleeping or sitting still not really exercising so let's zoom on into our chair and we'll see how this is effective now again at our lungs it's important that all three of these curves aren't being affected by are all three of these curves are shift brandish shifflett shift left is not affecting the percent saturation at the lung we're still staying at about ninety eight point five the big change is going to be here at the tissue so let's follow our new line up and bring it across now we're at about eighty five percent saturated so well this is weird what's going on here so while at rest while we are say shivering inside a classroom that the air is too is on too high or the heat is not working properly we can do some math so let's see what's going on here at our lungs we are 98 percent saturated right and again this is going to be arteries now we look at our new curve or shift left we say well what happened on the venous end we're down to 85 percent saturated and this is the venous end so now we have to do some quick math and say well what happened what happened at a tissue level we gained 13 percent oxygen this is how much was released thirteen percent of the oxygen was released into the tissues so the question is now why why did we lose less what less was needed this is called conservation we are conserving that oxygen we took all that time at 105 millimeters of mercury to find that oxygen to the hemoglobin now when we get to the tissues we are resting we're laying down our body's cold so we are releasing less oxygen into the tissue so when can this become problematic well it could become problematic with say hypothermia and this is where people run into big issues if you submerge yourself in to say freezing water if we go back to say the Titanic right and all those people fell into the ocean and it was freezing cold and they died I say well how did they die while their systems shut down but more importantly we were delivering less and less oxygen to their tissues to their organs now here's what becomes tricky from a nurse perspective you put a pulse oximeter on a patient's finger and it will still read 98.5 percent although with extreme cold sometimes when we get vasoconstriction to our digits and our extremities it will not give an accurate reading anyways but let's assume that we're getting an accurate reading this gives the illusion that the body is oxygenating adequately enough but in reality we're only giving 13 percent or less to the tissues and the tissues could become hypoxic now we have one more curve to talk about and we're gonna put this one all the way over here and we're gonna make it green and this curve is going to be fetal hemoglobin okay so this curve is way over here to the left and we say what's going on here so we can add to shift left so shift left we can add fetal hemoglobin so why what's going on here why is there such a shift left now whenever we shift left whether it be everything in blue here that shift left or fetal hemoglobin shift left we have to understand that the affinity for oxygen is increasing is increasing and this is important because this is how strongly oxygen is binding and staying stuck to hemoglobin so to say why why is fetal hemoglobin so different well remember mom the baby is not breathing right doesn't have the ability to oxygenate his blood on its own so what we essentially make here is a Monster Magnet right a super magnet so as fetal hemoglobin passes through the placenta and mom's blood is also passing through the placenta remember they are not mixing they are intertwined the blood vessels are intertwined around the blood the placenta will see that this super magnet this fetal hemoglobin will physically rip the oxygen off of moms hemoglobin and suck it onto its own hemoglobin essentially oxygenating its blood through this leaching or this super magnet type of effect so what happens when we see funeral hemoglobin well typically during pregnancy mom her curve will be in a constant shift right as 2/3 DPG is constantly increased temperatures slightly elevated etc so that concludes our oxygen hemoglobin dissociation curve I hope you found this little tutorial useful

this whiteboard tutorial is going to go through the oxygen hemoglobin dissociation or saturation curve so we&#39;re gonna be zooming in and out of hair so bear with me as we kind of zoom in to look at our little red blood cell so before we get into our saturation we have to understand what&#39;s going on with this red blood cell so remember that our typical red blood cell biconcave desk has no nucleus which is and can cause problems the question is how does it do work how does it get energy so we&#39;re going to talk about it first and foremost as being a sack of protein and you say okay well what&#39;s that protein we talked about hemoglobin right and we&#39;ll say that we have hemoglobin as a protein filling this sack and we say well how much hemoglobin and we tend to say that four oxygens bind to hemoglobin people just make that direct assumption that every red blood cell has one hemoglobin that binds for oxygen and we&#39;re good to go when in actuality we get per red blood cell roughly 270 million mmm hemoglobin molecules within each red blood cell again that&#39;s an average so then we go to our red blood cell and say well how does this this guy this thing do work well how does it get energy well we work through a process of glycolysis okay glycolysis and what this pretty much does is it takes glucose and it&#39;s gonna convert it to pyruvate and what this is gonna do is it&#39;s gonna give us the ATP we need in order for this cell to do work now we&#39;re gonna come back to this a little later because there is a byproduct of this right here that we are gonna have to talk about that does affect the oxygen saturation our next step in this process is to look at actual hemoglobin if we go back to our red blood cell that we talked about back when we did blood we remember that hemoglobin has four subunits and alpha 1 and alpha 2 a beta 1 and a beta 2 so we&#39;re not going to get too crazy with that right now but we do want to talk about how oxygen is going to bind to this hemoglobin so we have an oxygen molecule that comes in and it&#39;s gonna bind to our first hemoglobin and what this does is it&#39;s going to cause an increase so we&#39;re gonna change this to red and we&#39;re gonna cause an increase in the affinity of oxygen to its neighboring subunit so now oxygen is going to bind to the next one and it&#39;s going to increase the affinity of these subunits and then we see this cascading effect and then we get once oxygen binds to our second subunit we get an increase in affinity for the third subunit to bind and here comes oxygen binding even more affinity to that third subunit even stronger connection and so forth we go to an increase in affinity and the fourth subunit and oxygen is going to go and increase the affinity to bind oxygen to that fourth subunit this is called cooperativity so what happens is these guys are cooperating tivity they&#39;re cooperating with each other to bind more strongly each successive time for each subunit so that allosteric binding so in chemistry we call allosteric binding the allosteric binding of oxygen is going to increase as the subunits cooperatively work together so from here now we can make our board a little bit bigger so put our hemoglobin out into the corner and we&#39;re gonna draw ourself a saturation curve and we&#39;ll call it our oxygen hemoglobin the association association curve so now we can start labeling our axes and putting in some number so we&#39;re gonna put a zero here we&#39;re gonna call this side our percent saturation of hemoglobin and we&#39;re gonna call our x-axis our partial pressure of oxygen and we&#39;re gonna put it in millimeters of mercury now we can start putting some numbers here let&#39;s mark this is 10 20 30 40 50 60 70 80 90 a hundred and we&#39;re gonna go half to a hundred and five remember that we said the partial pressure at the lungs is a hundred and five millimeters of mercury then we&#39;re going to go up our y-axis and we&#39;re going to do the same thing 10 20 30 40 50 60 70 80 90 and 100 now let&#39;s draw our sigmoid shape curve so we&#39;re gonna start at 105 and we&#39;re gonna try to maintain this curve I&#39;m gonna come straight down into zero so let&#39;s explain what&#39;s going on here let&#39;s go up to 105 and we&#39;re gonna drop a dashed line down to 105 and we&#39;re going to see that we have 98.5 percent saturation at the lung so we&#39;re gonna change colors and we&#39;re going to do this and we&#39;re gonna bracket a couple of regions and we&#39;re going to explain what&#39;s going on here so our first bracketed region is what&#39;s going on at the lungs and systemic blood vessels Oris okay and then this second dashed line is going to be what&#39;s happening at a tissue level okay so let&#39;s go we&#39;re gonna switch again to red so that we can understand what&#39;s going on here so remember that hemoglobin and oxygen are going to bind they&#39;re gonna bind specific pressures we could put an analogy we think about a magnet take two magnets and then take the positive end of both magnets and try to push them together you&#39;ll feel that they push apart so the question is well how do you get those two magnets that technically don&#39;t want to stick to each other to touch and the answer is well pressure you can apply a specific amount of pressure to get those ends of those magnets to touch oxygen and hemoglobin are no different oxygen human will technically do not like each other they&#39;re going to repulse each other but if you apply a specific amount of pressure specifically here a hundred and five millimeters of mercury we will get 98.5 percent of oxygen binding to hemoglobin now we have a range so this green range that we just outlined is going to be so right here is going to be the saturation at the lungs and then as it carries those systemic arteries and this is good because look as we travel down this line right and we&#39;re in those arteries the partial pressure is decreasing as we expect it to until we get to the tissues but the way the affinity for oxygen the way that oxygen is binding to hemoglobin isn&#39;t changing we&#39;re staying right at about ninety eight point five percent and this is good because this is what we want and this is what we expect if you go back to what we just said we said that oxygen is going to by ninety eight point five percent of it is going to bind at the lung level right so we&#39;re loading oxygen at the lungs and then at the tissues we have to get rid of it we have to unload it so how do we do it with pressure so now we can go back and like Penn marker and we go back to our tissue level now remember in our tissue level we were at 40 millimeters of mercury and we follow this all the way up our chart and we see sorry that line is not that straight and we see that we are about 75% and that&#39;s what we expect right so at the tissue pressure drops to 40 millimeters of mercury and we follow our chart and we see that 75% is now bound so what happened right what happened to the oxygen what happened to the affinity of oxygen for hemoglobin so now we can say what&#39;s happening we&#39;re gonna put some numbers to this and we&#39;re going to look at an arterial end and a venous and so if we look at Anna Tyrael end right by the time we get to the tissues we have 98% of hemoglobin is bound okay so then what happens pressure decreased decreases to 40 we get 75% of oxygen is still bound to hemoglobin so what happens so we get a net so we say 75% of hemoglobin is bound this is going to be arterial and this is going to be venous end so what happened to that 23 percent so we do a quick math problem we subtract 98 from 75 and we see that 23 percent of that oxygen that was bound to hemoglobin in the arteries was released into the tissues okay now again we&#39;re naming this as being normal this is you just sitting still not really doing anything this is our normal saturation curve okay so we&#39;ll just recap and we say okay well just sitting here doing really much of nothing and everything temperature and everything being constant we see that our lungs is doing its job we&#39;re loading up ox 98.5% as we travel through those systemic arteries we now drop the pressure in the tissues to 40 and percent saturation went to 75 so now what happened to the affinity for oxygen as pressure decreases pressure decreases we went from 105 to 40 millimeters of mercury the affinity for oxygen went down okay the affinity went down which means that we started letting up on the pressure on back to our analogy the magnet and they started pushing apart so again misconception people think that we load up on two percent of oxygen that the lungs that we deliver a hundred percent at the tissues this is not the case we are only losing roughly 23 percent now this curve is dynamic it changes every second of every day with a few factors so what we&#39;re gonna do is we&#39;re going to shrink our chart down we&#39;re gonna make our whiteboard a little bit bigger and we&#39;re going to look at some factors that affect this normal dissociation curve now we&#39;re going to talk about things that&#39;s going to affect this curve so we&#39;re going to kind of slowly erase some of the things we wrote and introduce some new lines here more precise okay now we have our chart back let&#39;s get our line back so let&#39;s see what effects this curve so things that can affect this curve we&#39;re gonna use this pneumonic so we&#39;re gonna shift this curve right and we&#39;re gonna shift it left so we&#39;ll see what effects the shift right there no Manik we&#39;re going to use is cadet face right okay so if you think about the military when you have soldiers and training they&#39;re called cadet and when they are made to stand in line they face right so a right shift curve follows the mnemonic cadet so we think about things that will start with this letter so first is going to be for carbon dioxide the a is gonna stand for acidity the D is gonna stand for 2-3 BPG so-die phosphoglycerate or 2 3 2 3 bisphosphoglycerate we&#39;ll talk about what that is in a second the EES gotta stand for exercise and the T is gonna stand for temperature okay now what happens to a shift right let&#39;s use a red line to draw a curve shifting right so we have a rightward shift now what causes that shift right and we&#39;ll make this red arrow here is going to be an increase in co2 an increase in acidity an increase and 2 3 bisphosphoglycerate which is seen elevated in pregnancy and this makes sense because those red blood cells are going to be doing more work and before when we talked about that byproduct and we&#39;re gonna zoom on in right here we talked about that by-product that we were going to talk about later of glycolysis well here it is and the byproduct that we are going to be talking about is 2/3 B P G no I&#39;m gonna zoom back out and kind of move back over to our shift and we&#39;ll say ok well an increase an exercise and an increase and temperature and all this makes sense right and we&#39;ll get into that carbon dioxide oxygen shifting in the red blood cell but as you exercise you be coming to an oxygen debt and that you have to repay that oxygen debted miss and we know from what we said before that hydrogen ions start popping off as you&#39;re moving more co2 so co2 increases because those hydrogen ions are filling that plasma in that blood we get an increase of a city because the red blood cells are doing more work we get an increase in to 3 BPG and again goes with exercise in our body temperature will increase so let look at our saturation or percent saturation how does this affect the curve so we look over here and we say okay at a tissue level and we follow it up we follow it up and we say good nothing is changing not at all so we get 98.5 percent saturation at the tissue level and this is good this is what we want so we&#39;re breathing in and we&#39;re binding 90.5 all the oxygen that we could bind to even globin is binding where is the change let&#39;s follow our tissue level up we go to 40 big change we are now getting 50 percent saturation so what does that mean let&#39;s go back to our calculations and we say ok on the arteriole end we are binding 98 well make this a little smaller so we have a little more room we&#39;re binding 98% so at 105 millimeters of mercury through arteries on our lungs and our systemic arteries were 98 percent bound a FEMA globulin of hemoglobin bound by oxygen now as we decrease down to 40 millimeters of mercury what happened in our venous so this is again arterial end and our venous end we are decreasing to about 50 percent of saturation so what happened here if we do a quick math problem like we did before 98 minus 50 is 48 so we are getting 40% of that available oxygen delivered to the tissues and this is smart so if we zoom back out and go back to things that are causing this exercise is causing a shift right increase in temperature shift right on a really hot day when you&#39;re sweating your oxygen saturation curve is going to shift right again dynamic these are things that are happening all day long Oh to co2 is increasing acidity is also creasing so what do we do we have to repay that oxygen debted miss this curve has to be dynamic we have to be able to adjust the rate of release of oxygen to the tissue and we did 48 percent we doubled more than double the amount of oxygen being delivered to the tissue with a shift right so think about that in a common-sense way this is what we expect we&#39;re entering to the oxygen debt the pressures were meaning the same we cannot affect we cannot change the pressure in our body but we what we can change is how tightly how strongly how the affinity for oxygen the affinity for oxygen to hemoglobin we could affect that so by shifting this curve to the right we decrease the affinity of hemoglobin to oxygen so while we get to 40 millimeters of mercury more oxygen is being delivered to our tissues now we&#39;re going to take this and we&#39;re going to move this out of the way so that we can so let&#39;s go ahead and now let&#39;s erase to write for shift left okay now let&#39;s go back to our pencil let&#39;s change our color now we&#39;re going to shift this curve to the left so let&#39;s zoom in we&#39;re gonna draw a curve follow our same line and now we shift left now what does this mean what&#39;s happening here so it&#39;s gonna be the opposite co2 is going to decrease acidity is going to decrease to 3d PG is not really a factor here but exercise will decrease temperature decrease when can this happen if you are sitting in a lecture room that is is extremely cold and your temperature goes down your oxygen saturation curve is going to shift left then we&#39;ll see what that means that a percent saturation how that affects percent saturation our co2 is going to go down because we&#39;re not exercising the levels of co2 is not increasing respiratory rate is not increasing which means acidity is now going to go down because our cells are red blood cells are well oxygenated okay and we&#39;re at rest sleeping or sitting still not really exercising so let&#39;s zoom on into our chair and we&#39;ll see how this is effective now again at our lungs it&#39;s important that all three of these curves aren&#39;t being affected by are all three of these curves are shift brandish shifflett shift left is not affecting the percent saturation at the lung we&#39;re still staying at about ninety eight point five the big change is going to be here at the tissue so let&#39;s follow our new line up and bring it across now we&#39;re at about eighty five percent saturated so well this is weird what&#39;s going on here so while at rest while we are say shivering inside a classroom that the air is too is on too high or the heat is not working properly we can do some math so let&#39;s see what&#39;s going on here at our lungs we are 98 percent saturated right and again this is going to be arteries now we look at our new curve or shift left we say well what happened on the venous end we&#39;re down to 85 percent saturated and this is the venous end so now we have to do some quick math and say well what happened what happened at a tissue level we gained 13 percent oxygen this is how much was released thirteen percent of the oxygen was released into the tissues so the question is now why why did we lose less what less was needed this is called conservation we are conserving that oxygen we took all that time at 105 millimeters of mercury to find that oxygen to the hemoglobin now when we get to the tissues we are resting we&#39;re laying down our body&#39;s cold so we are releasing less oxygen into the tissue so when can this become problematic well it could become problematic with say hypothermia and this is where people run into big issues if you submerge yourself in to say freezing water if we go back to say the Titanic right and all those people fell into the ocean and it was freezing cold and they died I say well how did they die while their systems shut down but more importantly we were delivering less and less oxygen to their tissues to their organs now here&#39;s what becomes tricky from a nurse perspective you put a pulse oximeter on a patient&#39;s finger and it will still read 98.5 percent although with extreme cold sometimes when we get vasoconstriction to our digits and our extremities it will not give an accurate reading anyways but let&#39;s assume that we&#39;re getting an accurate reading this gives the illusion that the body is oxygenating adequately enough but in reality we&#39;re only giving 13 percent or less to the tissues and the tissues could become hypoxic now we have one more curve to talk about and we&#39;re gonna put this one all the way over here and we&#39;re gonna make it green and this curve is going to be fetal hemoglobin okay so this curve is way over here to the left and we say what&#39;s going on here so we can add to shift left so shift left we can add fetal hemoglobin so why what&#39;s going on here why is there such a shift left now whenever we shift left whether it be everything in blue here that shift left or fetal hemoglobin shift left we have to understand that the affinity for oxygen is increasing is increasing and this is important because this is how strongly oxygen is binding and staying stuck to hemoglobin so to say why why is fetal hemoglobin so different well remember mom the baby is not breathing right doesn&#39;t have the ability to oxygenate his blood on its own so what we essentially make here is a Monster Magnet right a super magnet so as fetal hemoglobin passes through the placenta and mom&#39;s blood is also passing through the placenta remember they are not mixing they are intertwined the blood vessels are intertwined around the blood the placenta will see that this super magnet this fetal hemoglobin will physically rip the oxygen off of moms hemoglobin and suck it onto its own hemoglobin essentially oxygenating its blood through this leaching or this super magnet type of effect so what happens when we see funeral hemoglobin well typically during pregnancy mom her curve will be in a constant shift right as 2/3 DPG is constantly increased temperatures slightly elevated etc so that concludes our oxygen hemoglobin dissociation curve I hope you found this little tutorial useful

Transcript for:Oxygen-Hemoglobin Dissociation Curve

Transcript for:
Oxygen-Hemoglobin Dissociation Curve