hi everyone and welcome to today's lecture on metabolic integration so I'm going to try to keep today's lesson short for you but basically the whole point of today's lecture is to show you that all of the different Cycles all of the different metabolic events that we talked about throughout this course are all interconnected okay you could see how the intermediates and the products from various cycles and and metabolic pathways that we talked about end up being used towards other Pathways we talked about and this figure here shows that there are various organs that are related to these processes and help for them to occur and we're going to go one by one through each of these organs throughout this lecture but I want you to Circle star highlight the liver and make note that that is the metabolic Hub that we're going to mention a few times throughout this lecture so now as promised we're going to go one by one through the organs we start off with the organ that many of my undergrads do not know about or use uh that is the brain and the purpose of the brain is that it is the control center of our bodies now what I want you to remember about this slide and so many students remember it for for many semesters later is that 60% of the body's glucose is required by the brain and I always make fun that you know I make the joke that I'm pretty sure that my students only use about 20% of that but um please make sure in your notes you remember 60% of the body's glucose is required by the brain and I like to emphasize that because in today's society especially in our Jim brro culture um a lot of people are so scared of sugar of carbs uh you know anything with glucose in it and yes too much of these things is problematic and bad for the health overall but keep in mind too little is also a problem for you and think about if you've known anyone who has given up sugar you notice that what are they lethargic and a lot of times they have brain fog and they will not think as clearly or as smart uh in terms of their decisions and their process is when it comes to having deprivation of sugar okay so you know that's that's like me sometimes but make sure to highlight that in your notes so now the two organs that we're moving on to in this slide are the pancreas and the intestines and the pancreas that's going to be important in terms of the glucose that we just mentioned moment moment ago in terms of regulating that in the blood and in the body because the pancreas secretes insulin and it does that when blood sugar levels are high okay so after you've had a big meal for instance you will have a spike in your insulin levels and in later slides today we're going to go through that process why that happens what's the consequence but for now make note that the pancreas is responsible for secreting insulin it also secretes d digestive proteases that we've mentioned in some of the other lectures already so for instance if you remember tripon and kimot tripon when you had to uh do that lovely sequencing in terms of breaking down proteins I know you guys love that one but yeah so um the pancreas is responsible for secreting things like Tron kimot Trion and lastas that basically help with the degradation of proteins that you have in your diet diet we then have the intestines and there are the small intestines and the large intestines and I want you to know the difference between them and that difference is in terms of what they absorb for you so the small intestines are responsible for absorbing nutrients whereas the large intestines they absorb water and electrolytes okay so both play a very important role in digestion and your overall health and dietary function but the difference is that small intestines absorbs nutrients large intestines absorb water and electrolytes now the small intestines also secrete some peptide hormones that control eating behaviors and we're going to talk about that in the upcoming slides then we move on to some other key players in terms of our metabolism we have the stomach and the liver as you know the stomach's main role is in digestion it basically gets the food prepared for the small intestines by producing what's called Kim and Kim is basically this acidic food slurry that helps you start in terms of digestion of your food now the stomach also just like we mentioned a moment ago uh a moment ago with the uh small intestines the stomach also secretes peptide hormones that control eating behaviors and we're going to talk about that uh a little bit later in this lecture then we have the liver and I want you to Circle star highlight that the liver is what we call the metabolic Hub and the reason why that is is the liver if you look at things like the figure um at the beginning of this lecture you see that the liver is the central processing facility that really connects a lot of the different metabolic pathways and cycles that we've talked about already in this course and it is basically a key player in glucose regulation because of those various metabolic cycles that it helps you know connect with other parts of the body and helps it in terms of really fueling our body and getting what needs to be uh sent to peripheral tissues and other organs okay and it's you know it's a it's heavily involved in the cycles and in terms of control Thea insulin glucagon and signaling that again we're going to talk about elsewhere uh in this lecture the other thing that I want you to Star and um I could I could say it the traditional way that students all wait for my little slogan of circle star highlight is that the liver also has what's called the portal vein and not only is that involved in you know delivering nutrients where they need to go but it's very important in terms of inactivating toxins from the diet and I want you to remember that not just for this class but in your life that the liver has the portal vein involved in inactivating toxins from your diet the reason I emphasize that is think about it this way if the liver is inactivating those toxins that tells you that the liver is the organ that is going to get contact with those toxins before they are inactivated so that's why things like having too much alcohol or taking in any kind of drugs destroy the liver and lead to a lot of bodily dysfunction from that and even death because the liver since it is responsible for inactivating these toxins it gets hit with it when those things are at their most toxic level okay so keep that in mind throughout your life and really make sure to take care of your liver and kidneys because it is not a fun time in your life if anything happens to those two organs now I just want to take a moment away from the organs to talk about an important intermediate which we've seen before in our cycles and that's glucose 6 phosphate and when I ask what are some of the fates of glucose 6 phosphate it's actually highlighted in this figure here very nicely so you see glucose 6 phosphate in the center here here and you see those arrows showing four of the possible fates for glucose 6 phosphate one it can be used to go toward the pentos phosphate Pathways which we've talked about already two it can be released uh toward getting glucose released into the blood so you know getting proper glucose levels in the blood over here glucose 6 phosphate can feed toward glycogen synthesis and then down here glucose 6 phosphate can lead toward glycolysis and then things like aerobic and anerobic respiration okay so these are the main fates of glucose 6 phosphate so now continuing on with the parts of the body that you know basically are connected to the metabolic pathways that we've discussed so far in this course we now move on to the muscles and we have two different categories that I want you to be aware of skeletal muscle and cardiac and the difference between them that I want you to know is that when you think of skeletal muscles these are basically activated in Rapid bursts and utilizing endurance activities and they could even be an energy source during times of starvation whereas your cardiac muscle you don't want them doing that you want your cardiac muscle active continually in a nice steady fashion over the course of your entire life and you certainly do not want them being broken down at any time not you know not even in times of starvation so that's the difference that I want you to be aware of between these two types of muscles now another little Divergence away from the body parts and and organs is the concept of creatine kise and so I'm going to use my little laser pointer and highlight the reversible reaction that this enzyme will be catalyzing basically it's a reversible phosphor transfer reaction okay and so you have that um that reaction in order to generate ATP in muscle cells so that you know it's readily available as a source of energy for muscle contraction and now when you think about that you know it's the idea that um you know when you enter the medical field or even when you're looking at your own blood tests and whatnot they can utilize this reaction and looking at creatine or creatine kinase levels in order to analyze whether or not you have muscle damage okay so make sure to Circle star highlight that in your notes because it's nice whenever we can make connections to our everyday lives or to the medical field now the next thing that I want to point out is adapost tissue and I know not everyone wants to hear about atap POS a lot of us try to get rid of it but atap POS is very important this is the body fat storage tissue and that means that it's a great storage of energy now there are two different categories that I want you to know the difference between there's subcutaneous fat and there is visceral atopos or visceral fat and it's important to know the difference because they have very different outcomes in terms of health so subcutaneous when you look at this word sub means under and cutaneous means Skin So subcutaneous atopos is directly under your skin you will find it in places like your thighs your buttocks your arms your face and that's different from visceral fat and visceral fat I want you to underline VI of visceral fat and then write vital organs so underline VI visceral and VI of vital vital organ because visceral uh atopos or visceral fat is what's located in your abdomen and this abdominal fat is critical to remember because that's the fat surrounding vital organs and it can secrete things like atpa and so you know it'll basically be secreting peptide hormones that are involved in metabolic homeostasis but what's important to look at here is that since visceral fat is located around your vital organs that is going to be the fat that is most highly associated with a higher risk of cardiovascular disease and I want you to Forever remember this picture because it's kind of traumatizing when you think about it this shows you visceral fat so when someone has a lot of abdominal fat you may just picture that you know rest above organs no no big deal oh I just got to you know I just have a beer belly it's it's nothing not not much of a problem but now I want you to actually look at what happens to critical organs that is coated in fat okay and so that's going to impact how that organ is able to function and so I want you to you know have this picture imprinted on your brain so that you take things like physical health very seriously because ultimately we only have one life to live and so I want you to try and get the most out of that life you know if not for you then for your loved ones and the people who care about you speaking about loved ones and the people who care about you and taking care of physical health I want you to put little stars next to the kidneys because this is the you know the part of your body that I always tell students if you are in the medical field or if you are in you know the hospital with a loved one when a patient's kidneys fail that usually means they will be gone within a few days okay A lot of times it's two to 5 days or two to seven days later if you have a critical patient and their kidneys fail they are usually going to be a goner a lot of times you know by then especially with older patients dialysis will not be an option or will not be able to save them from you know the worst level of failure now the reason why the kidneys are so important is their function or their purpose is to filter your blood and to you know get rid of waste products from the blood now there are ways to try and help patients who have uh lower function of the kidneys or start to have some failure but not full failure of the kidneys and that's the big one is hemodialysis which is basically a procedure that uses the these semi-permeable membranes and the process of diffusion to help filter the blood for the per person now please do not think that that is you know kind of a a Saving Grace of oh I don't have to worry about my kidneys you know if anything happens I could just you know there's dialysis for that if you have ever had a loved one or you know known a patient on dialysis that is a brutal life it is not something I would would wish upon anyone they have to go 3 or 4 days a week for 3 to 6 hours hooked up to these machines and staying in these places because they got to check vitals and do prep before and after it is painful it is prone to sepsis and infections because of the ports that they need in terms of entry into and out of the body uh when my grandmother was doing it it was brutal on her and and her my her husband my grandfather and a lot of the loved ones around them and also it was painful for her to see that there were a lot of young people in there with her and unfortunately I keep mentioning this in the classroom too because of our what I constantly call Jim bro Society but I am part of it too um you know a lot of people have really gone full force into putting all kinds of supplements and powders into their bodies protein powders protein bars without really knowing the science of being able to read the ingredients and determine what is really healthy for you and what is problematic for you your liver your kidneys um and a lot of people you know unfortunately because they don't know science they'll of course believe the labels that say oh this is organic oh this is natural oh this is healthy sometimes things that say that when you read the labels aren't truly healthy you know some things that are organic or socalled natural are not safe for you so unfortunately the amount of people in their 20s and 30s who have kidney failure who have to be on dialysis who have CKD which is chronic kidney disease the amount of young people having this has skyrocketed because the amount of supplements and powders that they will put in their bodies and some of them will just order these things off of the internet without them even being FDA regulated or you know truly trustworthy so please be very careful what you put into your body and then we get to another one of those slides where I say to Circle star highlight please because this is the point that I have been making repeatedly in today's lecture that the liver is what serves as the metabolic Hub of the body and as you can see from here the reason we call it the metabolic hub is because it coordinates the exchange of metabolites between major tissues and organs and so basically it is a hub between or amongst the various cycles and metabolic pathways that we've talked about in this course and it especially involves the Import and Export and conversion of glucose and triog glycerols and I'm going to have a reminder in the upcoming slides about why why that is so important so as promised here is the reminder of why triog glycerols and glucose are so important here we have the triog glycerol cycle and basically as you can see from here the purpose of this is to maintain energy rich fatty acids in circulation so that they can be used by peripheral tissues and you see over here where you have fatty acids going to peripheral tissues now as you can see from this figure the Trias glycerol cycle is between the liver and the adapost tissue that we were just talking about a moment ago and so it's an interorgan process that continually circulates those fatty acids and triog glycerols and the big intermediate here and here that it is dependent on is glycerol all three phosphat so Circle star highlight that this cycle is between the liver and adapost and it is dependent on glycerol 3 phosphate and that will be both systemic and intracellular levels of glycerol 3 phosphate that's critical to this cycle now speaking of glucose we get to two very important hormones that you know a lot of you have probably heard of at least one of these and that first one being insulin and as we mentioned earlier insulin is going to be secreted when blood sugar is high so if you think about it right after a big meal or a snack you're going to have insulin secreted it's specifically secreted from pancreatic beta cells and if you use logic you can kind of figure out what's going on when you have this secretion so we just said that insulin is secreted when your blood sugar is high your blood glucose is high which means your body when it's secreting insulin the purpose is to try to lower or get rid of that glucose because it's high right now which means that insulin will stimulate things that lower the amount of free floating glucose which means stimulating glucose uptake by organs and tissues also activating glycogen and fatty acid synthesis because as you know glycogen is the stored form of glucose okay so that'll be important when blood sugar is high it'll also decrease your appetite through neuronal signaling in the brain that way you're not going to increase your blood sugar anymore okay now with everything in biology you need to have an opposite reaction to kind of keep things in control and so the opposite of insulin is glucagon and that's going to be released when blood sugar is low if you want you can kind of circle the a of glucagon to remind you that that one is going to be secreted from pancreatic alpha cells instead of beta cells and again you can use logic to think about why glucagon will be secreted and what it's going to do so we said insulin is secreted when blood glucose or blood sugar is high that means glucagon will be secreted when blood sugar or blood glucose is low what that means is if your blood glucose is low what do you want you want to increase it you want to make more or get more glucose how do we make more or get more glucose by stimulating gluconeogenesis or by stimulating the the breakdown of glycogen because remember glycogen is just stored glucose you chop it up you debranch it you have gotten glucose so glucagon is when blood glucose is low and it stimulates processes that increase glucose such as gluconeogenesis or glycogen breakdown it also will stimulate fatty acid export from adapost tissues when food is not available so now we're going to take a look at two other very important metabolic hormones and for this one I have a little trick for you to try and remember which is which so we're going to take a look at gin and leptin what I want you to do is in your notes when you write or say gin I want you to think of growling like the sound of your stomach growling because this is is the hunger hormone this will signal hunger and kind of trigger meal initiation it is shortterm fast acting you're going to know you're hungry like I said in the last slides everything in biology has an opposite so if gin tells you your stomach is growling and you're hungry that means leptin is the a opposite it is an appetite supressant signal and so basically this leptin signals that you are satiated and I absolutely love I smile every time the cutest little mice are what we call leptin deficient mice so you see the the negative here they these mice do not have the ability to register or you know produce uh leptin which means that they never feel SA iated they do not have that appetite suppression feeling and so they are always hungry which is why this poor little guy is like twice the size of the wild type little mouse the one that has proper leptin now when we talk about this slide it's very important in your everyday life because there's something called leptin resistance and basically if you are leptin resistant that means that your body is not going to be able to properly uh respond to leptin so your brain won't be able to register those signals you'll have you know reduced sensitivity of your receptors to leptin which means you are not going to properly be able to suppress your appetite or feel satiated and so if you've ever seen uh news stories or they even have TV shows about people you know who weigh 600 lb 1,000 lb all of that you know some of these people people will judge them and make comments not realizing that their weight has nothing to do with self-control or making good life choices for some people they actually have a leptin resistance where they cannot feel satiated and so they are always hungry and so once you have determined that then you can take the steps to figure out what to do medically for that now the reason why I say this is important though in everyone's life because you can actually get mild levels of lein resistance even when you do not have the extreme levels that you see in those you know 600 lb th000 lb situations and I want you to Circle star highlight in your notes some of the things in your everyday life that can cause more of a leptin resistance which then leads to you having more weight gain uh you know a bigger appetite and a lack of appetite suppression so some of the things that can lead to leptin resistance are inflammation high fatty acids in your diet obesity and in the case of college students pay extra attention to stress poor sleep and high alcohol intake also High meat intake as well okay so especially as college students make sure to work on stress Management on proper sleep habits because this can lead to more leptin resistance and will make your weight uh more uncontrolled now speaking of weight and you know a Healthy Lifestyles there are three primary factors that can influence metabolic homeostasis which it means you know having regulated cell functions having regulated uh chemical reactions and have having regulated weight and the three primary factors are genetic inheritance nutrition and exercise and all three of these are so important because you need to maintain a healthy weight in order to significantly lower the risk of a lot of different diseases and disorders including type 2 diabetes cardiovascular disease some types of cancers and even things like stroke and aneurysm so please make sure to take good care of your health cuz like I said before you only get one life to live now unfortunately some people turn to drugs or medications and and uh calorie substitutes in order order to try and lose weight which I always of you know say I recommend not doing that a lot of times the impact that drugs and medications and um calorie substitutes can have on your body ends up being even more unhealthy than some of the weight issues that you would face so now the ones that I want you to be aware of first off for weight loss we have aedine a fedrin will stimulate your adrenergic receptor signaling through the release of nor epinephrine and you can think of you know oh fight or flight when you think of you know Pathways like that which tells you that you have an increase in metabolism if you have an increase in your catabolic and anabolic reactions you will have an increase in weight loss similar to that is also lorcaserin uh which also goes by the name Bic and with that one that's an appetite suppressor but instead of acting on nor epinephrine it's a receptor Agonist for serotonin so it's working on the serotonin pathway but again if you think about those Pathways it helps in terms of energy expenditure and um in terms of your metabolic rates then we have orat which is also known as Zena that's a pancreatic lipase inhibitor and so if it is inhibiting lipases that basically tells you that the Trias glycerides or the lipids that would be broken down and stored in your body are instead going to pass through the digestive tract without being metabolized and so they will not be worked upon you will not be storing them and instead they just get excreted quickly the last one is my favorite one to teach because I actually knew some people who um who would eat products during the the time that Ales Ra was a big fad so what alestra is is unlike the other three the other three are drugs for weight loss alestra is also for weight loss but instead it was a zeroc calorie fat substitute that was put into foods such as chips so like Pringles and Lace potato chips for a while they were using olestra now that sounds great oh you can put zero calorie fat substitute now I could eat chips or other junk foods that they were putting it in or regular Foods the problem with this is it turned out to be what's called a greedy chemical meaning Not only was it not giving you fat but it was blocking the absorption of key vitamins okay key vitamins now that sounds like a dangerous problem right you would think that the government or the country banned this it has not been banned even to this day and what's most troubling about that is the reason why I laugh it was not only a greedy substitute meaning blocking vitamin absorption it also had this very weird and disgusting side effect that it caused anal leakage which they wrote on labels as oily stool or loose stool and so the funny part about all of this is instead of banning this greedy chemical they put labels like this on products and this is a real label I forgot if was on Pringles or some sort of chips but this was a real label and it's funny because you notice they put like oh we added vitamins but if you're reading it carefully well if it's inhibiting the absorption no matter how many vitamins you put what why like how is that going to help you and more importantly if it's causing abdominal cramping and loose stools meaning people who were using this in their underwear and their pants they would just randomly get loose excretions like it would be this oily discharge it's not like oh they had to fart or they had gas and then it happened no people were just having oily discharge come out of their body yeah anytime any place so yeah we we live in a country where people are you know scared of healthy safe vaccines but are willing to eat potato chips that make you practically leak oils from your butt but yeah welcome to American society so now yes if you look it up this is still not banned so be careful most most things don't use it anymore but just always be careful what you're putting in your body especially the weight loss stuff now people are using even more dangerous things like OIC and and drugs that were meant for people with diabetic issues and all but you have to really look into the science behind things and realize that those are not the ways to go taking things like OIC or weight loss pills are very dangerous in the long run and they end up leading to more damage to your body less health and even increase weight gain down the line so always try to do things the the natural healthy way with individual smart scientific choices in your everyday life rather than trying to rely on drugs or medications or social media you know whatever they social media tells you the last thing that I want to teach you about today is glycemic index whenever you see GI or glycemic index we're not talking about GI tract we talking about glycemic index here the meaning of that is basically the numerical value that will show you how fast glucose is released into the blood after you've eaten a food product that has carbohydrates in it and in in you know lesser lingo or or an easier way of thinking about it you can think about glycemic index is being how much a particular food will spike your sugar okay your blood sugar and you know how quickly after you eat a meal this will happen and so when we look at tables like this and you see glycemic index numbers any food with a glycemic index less than 55 so the lower the glycemic index the healthier the carbohydrates in that food are considered to be and the lesser the impact will be on your blood sugar level okay so you can eat the you know plenty of those foods without having a spike in blood sugar without having the lethargic you know nausea or bad reactions that you get when you eat too much sugar at once or too much of a high glycemic food now any anything above 55 and you'll notice that 55 Mark is kind of arbitrary I usually say lower healthier higher not as healthy because you'll notice that some of the things that are less than 55 well pound cake chocolate bar here it's not you know the healthiest of of foods to have in large quantities so anyway the higher the glycemic index the less healthy the food will be and the bigger the blood sugar Spike will be and you tend to have a very horrible feeling you know after you eat something that has a high glycemic index because think about it this way if a food has a very high glycemic index it's going to spike your blood sugar what happens according to our lecture today when your blood sugar increases when you have high blood sugar well your body pumps out insulin so if you had a big spike in blood sugar your body's going to pump out a bunch of insulin all of a sudden what's the purpose of insulin to drop your blood sugar but now because you had such a big spike with this high glycemic index food you had such a surge of insulin that now your blood sugar dropped from the insulin doing its job dropped to below your basil level meaning your normal level of blood sugar so now your blood sugar plummeted too much too quickly and so now you are going to have that lethargic that you know very fatigued yucky feeling because it plummeted and then now you're going to have the opposite uh in terms of instead of insulin now that your blood sugar went too low glucagon is going to get knocked in and and secreted and so now that's going to make the blood sugar go up more again okay now it's interesting the last thing I want to mention over here is when that happens when you're thinking in terms of high and low one of the ways that you can avoid that problematic surge in blood sugar and lethargic impact as your blood sugar spikes then plummets is to pair a high glycemic index food with a low glycemic index food so it actually ends up averaging out and balancing to reduce some of the impact so mathema Al I know it sounds weird but mathematically it balances so I always make this the joke to have a little bit of broccoli with like your ice cream or have broccoli with um a lot of your meals and what's interesting with that I want to point out uh cooking some foods can also impact the glycemic index so here when it says a glycemic index of 10 for broccoli that's actually raw broccoli when you cook broccoli it then raises it to about 35 or 45 but it is still considered a low glycemic index food you know lower than that 55 level so always try to pair anything that's high glycemic with low that's why if you have something sugary like a doughnut or whatever if you have a salad at the same time you'll notice that salads are really good pallet cleansers but they also ease some of the nausea or fatigue that you may get with meals and they refresh you part of that is because they are balancing your glycemic index in terms of that meal and they are helping you not to have the kind of spikes that you would have otherwise okay so that's what I was talking about before when I said to try and make healthy scientific choices every day in every decision that you make okay that is it for today's lesson please make sure you send me the answer to this review question in the remind app as soon as you get to this slide right now so pause the video send me a picture of the slide with your answer okay and thank you and have a great day as always any questions any concerns just message me in the remind app or email me since you know I have no life okay