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Current time:0:00Total duration:6:20

Video transcript

in order for our bodies to function properly the pH of our blood has to be within a fairly a fairly narrow range our pH so the pH of blood needs to be between seven point three five and seven point four five if you get if the pH falls below seven point three five you're going to be diagnosed and you know this this line is is you know there's kind of a gray area here but this is what's defined by the medical community if your pH devolved below seven point three five you are actually you are actually diagnosed with acidosis your blood is becoming too acidic you have too high of a hydrogen ion concentration in your blood or a hydronium concentration in your blood if your pH if the pH in your blood gets above seven point four five you're diagnosed with alkalosis alkalosis your blood is too alkaline it's becoming too basic the the hydrogen concentration hydrogen ion concentration in your blood is getting too low and so you might say wow you know this feels like a fairly narrow range how does how does blood how does our body put up with acidic things acidic molecules entering our blood or basic molecules entering our blood how can it handle that without our pH being able while keeping our pH in this range right over here and the answer lies in something that's also useful for the transportation of carbon dioxide in our blood and this right over here this these equilibrium reactions we see that carbon dioxide when you put it in the blood which is primarily water so carbon dioxide an aqueous solution it will react and we have some enzymes that help this that help this along but it will react to form carbonic acid so let me write this down it will react to form carbonic acid which is a weak acid this is carbonic acid and then that can dissociate to form bicarbonate so let me write that over here by carbonate bicarbonate and and a hydrogen ion or when we know that that would just attach to a water molecule and become a hydronium ion and so why is this useful well I said it's actually part of the carbon dioxide transportation in the blood because based on the sources I've looked at about about five to ten percent of your carbon dioxide can just dissolve in the blood and then also another roughly five or ten percent can actually can actually bow can actually be bound to hemoglobin and be transported that way but the bulk of it actually needs to go through needs to actually be be transformed needs to react to become carbonic acid and bicarbonate in order to be transported in fact in your blood the cut most of the carbon dioxide in your blood is actually in this form right over here and in particular bicarbonate and the sources I look at it eighty to ninety percent of the carbon dioxide in your blood is being transported in these forms and primarily and primarily as bicarbonate so this isn't the topic of this video is that how what's it what's a useful way to transfer to transport carbon dioxide in your blood but this is why this is how we do it but the topic of this video is why this is also useful for maintaining our blood pH in this range because these equilibrium reactions between carbon dioxide carbonic acid and bicarbonate this is a buffer system this is a buffer this is a buffer system and the word buffer in our everyday language it refers to something that that it kind of smoothes the impact of something or it reduces the shock of something and that's exactly what's happening here let's think about remember these these are all equilibrium reactions this is a weak acid and you can even look at the the different constituents of these molecules and account for them you have one carbon here one carbon here one carbon there you have one two three oxygens there you have one two three oxygens there one two three oxygens there you have two hydrogen's two hydrogen's two hydrogen's but let's just think about what if you started dumping hydrogen ions in the blood so what if you what if you what if you were to dump what if you were to dump hydrogen ions what's going to happen well if you dump more hydrogen ions if this right over here increases well if actually let me put it this way if you were to just dump hydrogen ions and if you didn't have this buffer system then your pH would decrease your pH would go down and if you do it enough your pH you would you would end up with acidosis but lucky for us we have this buffer system and so if you increase if you increase your hydrogen ion concentrations Michalis Italia's principle tells us hey these equilibrium reactions are going to move to the left so the more the more hydrogen ions you have sitting in the blood the more likely they're going to bump into the bicarbonate in just the right way to form carbonic acid and the more carbonic acid that you have in the blood well it's less likely that you're going to have the carbon dioxide it reacting with the water to form more carb carbonic acid so as you add as you add more hydrogen ions they're just going to be stopped up by the bicarbonate so this equilibrium the set of equilibrium reactions is going to move to the left so you're not going to have as big effect on pH and similarly if you if you dumped if you dumped some base let's say you dumped you dumped some base in your in your blood right over here well instead of it just making instead of just making your pH go up and possibly give you alkalosis well now the base is going to stop up the hydrogen ions and then typically that would just make your pH go up but if you have if you have them if you have these things going down well then you have fewer of these to react and have the equilibrium reaction go to the left and so the reaction is going to move more and more to the right and so this reaction you're just going to have more carbon dioxide being converted to carbonic acid being converted to bicarbonate this whole thing is going to move to the right and so it's going to be able to some degree replace the lost hydrogen ions so this right here is a buffer system it helps dampen the impact is if you have more hydrogen ions enter the system or is if you have something sopping up all of the hydrogen ions and it's super important for us well just just being able to live and frankly all mammalian systems
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