hi everybody and welcome back to miss angler's biology class i am miss angler in today's video we are going to look at homeostasis and we're going to look at one of the next pieces in the puzzle which is carbon dioxide and how we regulate carbon dioxide in our bloodstream if you are in grade 11 this particular topic suits you because you have to do the respiratory system and this ties in with that but if you are also in grade 12 you do need to know this content as well under your homeostasis section so i suggest that in grade 11 you take note so that you can carry this knowledge over into grade 12. now if you are new here don't forget to give this video a thumbs up and make sure you are subscribed and turn your notifications on because i post new content every tuesday and thursday if you are in a trick also you're thinking about getting an a in your finals you should think about joining my membership which is filled with live lessons extra members only videos and access to my study guide now let's get into some really important basics that we need to know about this topic before we go any further the body doesn't actually have the ability to regulate how much oxygen there is in the bloodstream rather it can only regulate how much carbon dioxide there is in the body and that's really important and it's often the mistake that is made in exam papers and answering questions people talk about the oxygen levels you can't regulate oxygen you can regulate carbon dioxide now something that goes along with regulating carbon dioxide is the function that co2 also plays in maintaining the ph of your blood now we need to maintain the ph of our blood because if we don't we run the risk of denaturing our enzymes which we have also learned previously about so when we are asked about the role that carbon dioxide plays in maintaining homeostasis and maintaining the ph of the blood we have to talk about them both at the same time so where exactly are we regulating carbon dioxide well it will surprise you in that it's not in the lungs we don't actually regulate carbon dioxide in the lungs we regulate the carbon dioxide in blood vessels in two very important blood vessels the first blood vessel is this one over here in your neck and there's one on either side it is called the carotid artery and this makes sense because this is the artery that is bringing fresh blood to your brain so your brain is going to be the first one to need oxygen out of all your organs it's what it's the most important organ so we want to keep a high oxygen content blood going up to the brain so if it picks up that there's too much co2 in the blood it's going to alert your body that you need to change the other blood vessel that is responsible for maintaining the co2 levels is your aorta which is of course your largest artery in the body this one down here now this makes sense right because the aorta is the blood vessel that is going to take blood to all the organs of the body so if it has high levels of carbon dioxide still in the blood at this point then we need to be alerting all of the effector organs and the breathing muscles to breathe faster and deeper so that we can exhale more carbon dioxide and inhale more oxygen so now let's get into how does this actually work how would you go about explaining this now you can use this exact answer to answer any questions in your exam or in a test and it follows the same structure i always use which is there's a stimulus a receptor a control center with a corrective measure and finally the effect of bringing about the change so speaking about a stimulus we need to start this process now as i mentioned to you earlier the body only responds to carbon dioxide levels so the carbon dioxide levels in your blood have now increased maybe you are exercising maybe you're not breathing properly whatever it may be it has now caused the co2 levels to go up now if that is the stimulus someone needs to receive that information and so that takes us to the receptors now the receptors in question are just called chemoreceptors and they are found in the aorta and the carotid as i mentioned earlier and they are stimulated and they pick up that the ph of the blood is lowering now that receptor needs to send information to somebody who needs to like read it and understand it they need to be the control center and so an electrical impulse is sent from those chemoreceptors to the medulla oblongata now i have a little picture of the brain here to refresh your memory of where that is and so we need to remember that the medulla is this region of the spinal cord just below the brain but just above the actual spinal cord when it exits out through the skull and so the medulla is a really important part of the body because it is responsible for your breathing rate now this important information has gotten to the medulla the medulla now needs to make a decision it needs to create what we call a corrective measure and so that corrective measure is an instruction of what to do next and it sends that to the heart and the breathing muscles and these two things happen at the same time so they're simultaneous the first message that goes out to the heart is saying that you need to beat foster why do we need to be faster because the faster we beat the more we circulate the blood the more the carbon dioxide and can be exhaled the second thing that needs to happen and this is again simultaneous at the same time the breathing muscles they need to work a lot harder and they need to contract faster and deeper and by doing so you are pulling more air in to the lungs and then diffusion of gases can happen again a lot quicker so if these are our two corrective measures together what happens is they combine their effects and they produce more carbon dioxide to be exhaled because that's the goal we want to get it out of the blood so that we can prevent what we call acidosis acidosis is the acidic ph of the blood and to some extent it needs to be there in very small amounts because as you have learned in the respiratory system it's important to break the bond between oxygen and hemoglobin and so you need an acid to do that for you but we want to keep that ph at a very minor margin in between a very very um small means in other words we don't want it to fluctuate too much we don't want the blood to be too acidic so we got to get rid of that extra carbon dioxide now as always and this is important whenever you're doing these kinds of questions you actually have to talk about how this assists in homeostasis so you must mention that you are going to return to the norm the norm being the normal amount of carbon dioxide in the blood and therefore not just the norm of carbon dioxide because always remember that this also links to the ph of the blood and the ph of the blood is now going to start to increase in other words it's going to become more alkaline less acidic and so that's why it's important to understand homeostasis and that it is maintaining the internal environment between narrow limits so if the ph goes up a little bit too high or a little too low we need to fix that and we do that with how much carbon dioxide is in the bloodstream now as always i like to finish off my videos with a quick terminology recap i'm going to walk you through these words you can use these for flash cards for easy revision if you're making mind maps and such and you should always use these words when you're explaining this topic because essentially these are the words that are going to get you the marks if they appear correctly and in the right context when you explain yourself so the first new word that we looked at was called a chemoreceptor those are the little cells that line your aorta and you're carotid and you would remember that those are the cells that are responsible for receiving the information that there is too much carbon dioxide in the bloodstream the aorta as we know is the largest blood vessel in the body and the carotid artery is the artery in your neck going up to your brain which is providing it with fresh oxygenated blood again i also want to stress the importance of knowing that the ph of the blood is really important because remember if the ph of the blood is too acidic or too alkaline it will result in the enzymes denaturing which we want to avoid now we spoke about the control center which is the medulla oblongata it is the region of the brain which is responsible for maintaining the breathing rate and finally we also spoke about what we call the breathing muscles which was the diaphragm and the intercostals and along with the heart these two things bring about the corrective change that must happen so that you can breathe deeper and then get rid of that carbon dioxide now if you like this video make sure to give it a thumbs up everyone and i will see you all again soon bye