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Current time:0:00Total duration:11:43

Video transcript

metabolism is just the flow of energy throughout the body energy enters our body when we eat food and that food is then absorbed in three different forms it can be absorbed as amino acids so things that make up proteins so you'd imagine meat would have a lot of amino acids or they can be absorbed as fats so these are lipids or fatty acids and so your greasy fried food it's pretty rich in fats or they can be absorbed in carbohydrates or I'll just write carbs here which you have a lot of an ice cream or other sweet things each of these things deliver energy into your GI tract your stomach and your intestines which can then be absorbed and sent elsewhere for use now carbohydrates are one of the main currencies for energy so let's focus on that and we'll do so by starting with glucose which is the most basic form of carbohydrates in fact it's considered a simple sugar now there are two main hormones that control the availability of glucose throughout the body and they're in a constant tug-of-war with each other one of them which you've heard of probably is called insulin insulin regulates the storage of glucose as we'll talk more about in a minute and the other guy on the end of the rope is a hormone called glucagon glucagon regulates the release of glucose from storage and it's pretty important that we have enough glucose available in the blood because for example the brain uses about a hundred and twenty grams of glucose per day and that's a lot because it comes out to be about 60 to 70 percent of all the glucose that we eat in a day but to put it in terms that I think you and I appreciate a little more 120 grams of glucose comes out to be about 250 MMS in a single day now that's a lot of MMS so you can see why it's really important to have enough glucose available for your essential organs to use and thankfully we have these two hormones to help regulate the amount of glucose our blood so now let's take a look at how these hormones regulate the amount of glucose in our blood and let's do that on this graph so let's say this axis represents time so over time we'll see some changes and this axis over here the Y axis will represent the concentration of glucose in our blood so that's the concentration of glucose and most commonly that will be represented in milligrams per deciliter milligrams per deciliter now the body likes to keep the amount of glucose in the blood to be no lower than about 70 milligrams per deciliter and no higher than about 120 milligrams per deciliter this is sort of the range that I would consider to be the mmm sweet spot because if we go any higher than 120 then we end up having a condition that's called hyper hyper meaning a lot of glycemia hyperglycemia which just means a lot of glucose in the blood if we have hyperglycemia for a long period of time that can lead to what's referred to as AI nerve and kidney disease eye nerve and kidney disease and we can go into a lot more detail about how this happens but just understand that having a lot of glucose in your blood can cause changes to these structures to make them not work as well and unfortunately this is a fairly common problem because another term for AI nerve and kidney disease is diabetes and in fact if you have a person who's been fasting overnight to come in for a blood test and you notice that they have more than 126 milligrams per deciliter of glucose on two different occasions that's grounds for diagnosis of diabetes on the other hand if we have very little glucose in our blood or not enough that condition is referred to as hypoglycemia hypo meaning less or low and then glycaemia of course meaning glucose and some of the things that you can start to notice if you're hypoglycemic that you're tired maybe you're lethargic but if this persists you can even go into a type of coma or even die from having too little glucose in your blood and in most people we start to notice that we're feeling hypoglycemic when we get below 40 milligrams per deciliter now usually our body's pretty good about making sure that the level of glucose in our blood stays within the sweet spot or within this sweet range and the way we accomplish this is through the hormones I just mentioned so let's imagine that you eat at this point of time right here and naturally the level of glucose in your blood will rise because you have introduced more glucose into your system by eating it eventually your body will notice that your glucose levels are rising and will counter that by releasing insulin to drive the amount of glucose in your blood down and that's an important point because insulin decreases the blood glucose concentration by storing the glucose in another form and we'll get into more detail about that in a second the other thing that could happen is that you may have a decreasing amount of glucose in your blood which as I mentioned here is not a good thing to have happen either what your body does to counter that is release glucagon to increase the amount of glucose in your blood and so it's important to remember here as well that glucagon will increase the serum or the blood concentration of glucose by releasing it from storage so glucagon does the opposite it releases glucose from storage so now that we know how the release of glucagon and insulin can affect blood glucose levels let's focus in and see how that happens so let's start with insulin and that does a number of things to glucose but remember that at the end of the day all we're doing is storing it just remember insulin causes storage so the first thing that insulin does glucose is cause it to undergo a process known as glycolysis glycolysis which you may have heard of before it's an irreversible process it's irreversible all right irreversible down here because it converts glucose into ATP which is the most basic unit of energy that we use in the body and that's an important distinction ATP is energy to be used anywhere in the body okay instead of storing the energy of glucose and ATP insulin can cause glucose to undergo what's called glyco Genesis glyco Genesis which just means the formation of glycogen so glycogen and glycogen is just a heavily branched polymer or molecule that has a whole bunch of glucose molecules stacked on top of it and this is just energy to be stored in the short term in mainly the liver or muscle tissue so mainly liver or muscle and this is a reversible process because once we make glycogen we can break it down and release glucose as well finally the last thing insulin can cause glucose to do is undergo lipogenesis lipogenesis which I think you can use the suffix to infer here that we are producing lipids or fatty acids lipids or fatty acids and this is an irreversible process so this is irreversible where we store glucose as lipid and the key here is that we are taking the energy of glucose and we are storing it long term long term in what's called adipose tissue adipose tissue or just the fatty layers within our body so adipose tissue now what about glucagon what are the processes it uses to release energy or glucose into the bloodstream let's put it this way if we're releasing glucose into the bloodstream my question is what are we releasing it from well the first thing we can release it from is glycogen and we just talked about this we can form glycogen using insulin or if there's a lot of glucagon around we can have what's called glyco glyco Gen ol Isis which means the breaking down or the cutting down of glycogen now this is a reversible process because we can always go and take glucose to make like a-- jinnah ghin the other thing we can release glucose energy from is or rather I should say are amino acids amino acids can undergo a process known as gluco neo Genesis so gluco meaning glucose neo meaning Anu and then Genesis meaning to create or the creation of this is also a reversible process that will take amino acids bunch them together with other things to convert them into glucose now finally the last thing glucagon can do is to take fatty acid so fatty acid or your lipid and instead of converting it to glucose glucagon will take the fatty acid and turn it into these things that are called ketone bodies ketone bodies and it does so through a process known as keto short for ketone genisys meaning to generate ketone bodies now this is an irreversible process and it's kind of a funky thing that happens within the body because it's what we do when we're in our starvation mode when we're not getting the right amount of nutrients for some reason or another and the reason why this is sort of a last resort is because ketone bodies are very unique in that they are energy forms of energy to be used only only by the heart and brain ketone bodies don't really supply energy anywhere else so that's why it's sort of a last-minute starvation mechanism to provide energy where it's most critically needed to help us survive so you can sort of see here that there's a tug-of-war game that goes on between insulin and glucagon in fact insulin itself when it's released into the blood will inhibit the release of glucagon which just goes to show you how opposite their end goals really are and there's a lot more to talk about how insulin is released or how glucagon is released and where it comes from this is a great overview of what they end up doing in the body