Heres a couple of words you might finduseful in the study of human metabolism. They too happen to be two messages that I enjoyin general. Brunch. Buffet. Id throw in all you can eat, butthats various kinds of showed, and then it would be six oaths, unless you hyphenate them. Butstill, brunch buffet! Youve get eggs and bacon and french toastand biscuits and fruit and some kind of weird sort of jello thing in there. And formerly youvepaid your twelve-ninety-nine, you know theres a pretty good chance that its all gonnaget devoured. But heres the thing. Not all that is you fit into your faceduring brunch-time is going to be handled the same way by your mas. After youre done grasping, some nutrientswill go straight to your people pile of trash to burn right away. But others willhave to be converted into something else. For example, the carbs and solids in your butteredtoast can be directly oxidized into useable energy, but the amino battery-acids in the bacon haveto converted to molecules that get broken down like carbs, if you want to get energyout of them.And while extravagance carbs and fatty can be storedin large, polymer different versions of their original patterns, any extra amino battery-acids cant be — they have tobe altered and then placed as fatty or glycogen. So, as Ive mentioned before, the moleculesin your person are constantly changing shape, and revamping and rearranging themselves toeither construct things or to use energy. And feeing food replenishes these nutrients– especially glucose. Then, depending on what your body needs, and when you last ate, specific hormones like insulin will help decide what to burn, and what to store for last-minute. This, of course, is an important function.Which is why things can go badly if this process doesnt work properly because of a metabolicdisorder, like diabetes. In that case, your form cant properly useand store nutritional vigour, which fixes the most acts of eating and metabolizing moredifficult, and possibly risky. Exactly how glucose stages can spike or sink, how we proselytize nutrients into vitality, and how all of that that relates to eating, andhunger, and weight, metabolism, and your state in general is — guess what? — complicated.But as you are a living thing that must eatin order to stay alive, Id say its worth read how it wields. And brunch is as good a place to start asany. Waiting in line for the all-you-can-eat brunchbuffet is a good time to recall the law of conservation of energy. The statute simply states that energy can neverbe created or destroyed; it can only change forms. And the processes of metabolism involves conversionsof energy — either through catabolizing reactions that freeing the vigor stored under your meat, or anabolizing ones that use or store that energy.So, you can enjoy your short-stack of flapjacksand biscuits and gravy, but remember: That power has to either get exhausted, or collected, somewhere inside you. Now, the conversion of food energy is partof the great balancing behave that is maintaining homeostasis, and one of its greatest tricksis cellular respiration. Cellular respiration is how we deduce energyfrom the food we ingest, specifically glucose, which is where most of our food points up. In order for glucose to become energy we canuse, we have to to give it some oxygen, and proselytize each sugar molecule into six moleculesof CO2, and six molecules of irrigate, that is generally causes about 32 molecules of ATP. Cellular respiration occurs in three simultaneousphases, where glucose broken up by glycolysis and other catabolic reactions; and then turnedinto pyruvic battery-acid and acetyl CoA; and finally directed into the Krebs cycle. Its all pretty complicated, but we coveredit extensively in Crash Course Biology, so rather than get into the blow-by-blow here, Irecommend you check out that video for a refresher.For now, merely remember that cellular respirationbreaks down nutrient molecules to generate ATP. And in doing so, it captivates some ofthe compound power that was in those ligaments for use in your form. Now, when it comes to how that energy is convertedand where, that depends largely on when you dine your last banquet. We all switch back and forth between two nutritionalstates — the absorptive, or fed nation — which is during or after ingesting — and the postabsorptive, or fasting regime, when the GI tract is empty and the body is running off of collected supplies. So, say youre just announce brunch-buffet, and youre still in the absorptive territory, unbuckling your region as your digestive systembreaks up the eggs and bacon and French toast and syrup into a bunch of mostly-glucose moleculesthat pass into your bloodstream. The first chip of glucose gets delivered throughoutthe body and is tapped to generate ATP on the spot, through cellular respiration. But since the dinner was big-hearted and rich, theresmore glucose moving around than your cadres need at the moment.And remember, ATP is too unstable to be usedfor storage, which intends all the extra glucose is gonna get placed as fatty or glycogen. And that storage is part of how you can endup earn weight !. Because: How much power gets collected dependspartly on your basal metabolic pace — thats the number of daily calories your figure needsto do business as usual. And that rate can be influenced by your senility, your sexuality, and torso size or structure. A young bodybuilder is gonna burn way more caloriesthan that insignificant grandmother, but generally, if youre sucking more nutrients than youreburning, you will gain weight. So yeah, for that you can blame the law ofconservation of energy. Now, of course all nutrients are important.I mean, your person is basically made of protein, so thats kinda key. But in terms of immediate ga, glucose isthe easiest beginning of nutrient for cells like your neurons.And it is always good policyto keep your intelligence well-fed, so it doesnt get hangry, or dead. So, your person likes to maintain a blood glucoselevel of 70 to 100 milligrams per deciliter. But gives say that, thanks to the buffet, youve now got 140 milligrams per deciliter. This means too much sugar is swimming aroundin your blood, and your organization isnt so pleased to see you both. If your blood sugar levels get too high, itcan detriment blood vessels, especially those in the nervous system, stomach, kidneys, noses, and terminus. Thats why diabetes is often associatedwith a higher risk of heart and kidney disease, loss of vision, and foot amputation. But frequently, rising blood sugar levels setsoff a series of occasions that trim them back up. Specifically, they trigger special beta cellsin the pancreas to start secreting more of the hormone that settles everything thathappens when youre in the absorptive mood. And this hormone is the all-powerful insulin. Insulins job in this instance is to moveglucose out of the blood and into storage.And to do that, it prompts a alteration from catabolicreactions to anabolic ones. For example, it articulates a stop to glycogenolysis, or breaking down glycogen in your liver and muscles to exhaust glucose for force, andinstead ramps up the process of glycogenesis, where extra glucose is linked together toform glycogen. It likewise activates lipogenesis, where verycool chemical reactions in the liver convert glucose to triglycerides and then ship themoff to your adipose tissue for storage. A similar thing happens with the additional fattyacids that you got from the eggs and bacon that arent immediately needed for energy. They get processed through lipogenesis, very, and are rehabilitated back into triglycerides, and then tucked away for a rainy day. The thing is, if youre thinking about this, all theselipids hate water, right? Fat and ocean dont concoction. So you should be asking yourself, how can they betransported in the blood, when theyre so hydrophobic? The refute is lipoproteins, four specializedproteins made by the liver that environ fatties and allow them to move in the bloodstreamas an emulsion. Youve probably heard of some of these.One is low density lipoprotein — also known as LDL cholesterol.Its what delivers some of the glucoseand solid that you merely ingest to your torsoes fatty accumulations. Another is high density lipoprotein — orHDL cholesterol, which is the good cholesterol. It starts out as an vacate protein packet sentout by the liver to gather up other cholesterols from the blood, and artery walls, and othercells. HDL then delivers the cholesterol back tothe liver, or to sits like the ovaries, testes, and adrenal glands, which use it tomake steroid hormones. Alright, so now your mas has put all theglucose and lipids and proteins where they need to go, and you can just coast into thepostabsorptive state.But some hours later, even though yoursmall intestine is still working on whats left of the buffet, your cadres have been helpingthemselves to the remaining glucose in theblood, and eventually your blood sugar level willstart to drop. Remember, your neurons are on an exclusiveglucose dinner schedule, so they need sugar at the ready. And if your body appreciations an imbalancein blood sugar levels, it sounds alarm systems. A decrease in glucose arouses alpha cellsin the pancreas to release insulins nemesis, the hormone glucagon. It starts parent the blood sugar level, bytriggering the liver and adipose tissues to metabolize their solid and glycogen collects, thereby secreting fatty battery-acids, glycerol, and glucose back into the blood.But if its been a day or two since youve eaten –for some reason — and youve burned through both your blood glucose levels and your glycogen storages, and you dont have any sugars turn left to feed your brain? In that case, your organization will launch into gluconeogenesis, and proselytize paunches and amino acids into glucose, so ATP synthesis can continue in your braincells. This process is a sort of last-ditch effortby the body to protect the nervous system from the damaging effects of low-spirited blood sugar. Now, of course, this whole system has flaws.And one of them is that the whole setup is almost entirely dependent on the suitable releaseand festivity of insulin. People with diabetes either dont produceenough insulin, or have abnormal receptors for it, which is why they often have to inject apharmaceutical account of the chemical after eating.Otherwise, their blood sugar levels will remaintoo high after eating, and theyll start pee-pee out large amounts of glucose to tryand balance the levels in their blood. The difficulty is, because glucose is being excretedand not accumulated, its not available when the blood sugar starts to drop, so the bodyhas to draw on fat and protein tissues for energy — which is one reason why abrupt weightloss can be an early signed of diabetes. Whether youre diabetic or not, I thinkwe can all agree it is important to respect your blood sugar levels, and retain to continuefeeding the monster. But, at brunch, merely — you know — use smallplates, and try to keep the outings to the buffet to under five or so.Today, you learned how your body gives energyfrom nutrient — including through cellular respiration, which converts glucose into ATP; glycogenesis, which proselytizes it to glycogen; and lipogenesis, which proselytizes it to triglycerides. And youalso learned how insulin regulates your carbohydrate stages. Thank you to our Headmaster of Learning, LinneaBoyev, and thanks to all of our Patreon patrons whose monthly contributions cure manufacture CrashCourse possible , is not simply for themselves, but for everyone, everywhere. If you likeCrash Course and want to help us save fixing videos like this one, you can go to patreon.com/ crashcourse. This bout was filmed in the Doctor CherylC. Kinney Crash Course Studio, it was written by Kathleen Yale, revised by Blake de Pastino, and our consultant is Dr.Brandon Jackson. It was directed by Nicholas Jenkins, editedby Nicole Sweeney; our chime decorator is Michael Aranda, and the Graphics team is Thought Cafe ..