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Glucose insulin and diabetes

Explore how glucose, a simple sugar, fuels cells in the human body. Understand the crucial role of insulin in glucose absorption, and learn about the complications that arise when this process is disrupted, leading to conditions like type 1 and type 2 diabetes. Created by Sal Khan.

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  • leaf green style avatar for user Mark
    How would a cell get access to insulin and glucose if it was not touching an artery or blood vessel.
    (8 votes)
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    • piceratops ultimate style avatar for user Django
      Great question. The shortest possible answer is 'Interstitial space'.
      Interstitial space is literally, the small opening or space between objects, and in this case, those objects are the cells. Diagrammatically, we show insulin in the blood stream attaching to insulin receptors on the cells. But more commonly, this insulin is pushed into the interstitial space through 'diffusion'. From there, Insulin floats around in the interstitial space, (the fluid between the cells). And these insulin molecules can essentially travel to the cells nowhere near blood vessels within the interstitial space.
      (13 votes)
  • female robot grace style avatar for user Ankita
    Are these the only types of diabetes or are there more?
    (12 votes)
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  • purple pi purple style avatar for user jodhamanvendra
    receptor are made of what?
    (15 votes)
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  • mr pants teal style avatar for user Kayvan Halperin
    What causes Type I and Type II Diabetes?

    Edit: As in what Environmental or Genetic factors, and is there different causes between the two?
    (4 votes)
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    • primosaur tree style avatar for user Christian Boada
      There is really no simple answer as the etiology of both of these diseases is multifactorial but I think I can give you a quick overview:

      Type I Diabetes is also known as juvenile onset diabetes or insulin dependent diabetes and it has an autoimmune origin that is very much related to genetic predisposition or other events (a common precipitant for this may be a viral or bacterial infection) that cause a production of antibodies that target the pancreatic cells responsible for making insulin (Beta cells) destroying them. This type of diabetes has a more sudden onset since the insulin deficiency is absolute and may lead to severe complication if not death if insulin is not administered.

      Type II Diabetes or Adult Onset Diabetes is defined as a "relative" deficiency of insulin, this may mean that there is a deficiency in the production of insulin or peripheral resistance to insulin. I would like to point out that there is no official "cure" for this type of diabetes and close monitoring of blood sugar is currently the best treatment option. The causes for these disease are of slow evolution and usually begin with a period of increasing peripheral resistance to insulin that causes the pancreas to compensate overproducing insulin (Insulin resistance stage) which after many years causes the cells to fail and the onset of full blown DM2. When the beta cells fail additional insulin needs to be administered tailored to the specific needs of the patient.

      Quick Overview:
      Type I, Causes: Mostly autoimmune with a strong genetic component (past medical history of lupus or other autoimmune diseases) but can also happen after a viral or bacterial infection. Sudden onset

      Type II, Causes: Polifactorial but very strongly influenced by the environment (diet) and obesity Slow progression towards full blown conditions that begins with peripheral resistance to insulin.

      P.D. If you want the specific genes that are related mostly to type I diabetes I have them but i didn't put them on here just to avoid confusion. Hopefully this is helpfull
      (9 votes)
  • mr pants teal style avatar for user Simeon Nichols
    Why do I see people with diabetes (I think type 1 probably) taking on extra sugar (for example from energy drinks) if it is Insulin they need; how does this help them? thanks
    (2 votes)
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    • old spice man green style avatar for user Alf Lyle
      Sometimes type 1 diabetics get into trouble because there is not nearly enough glucose in their blood. Cells must take in glucose in order to function, and insulin acts as a “key” to allow glucose to be transported into a cell. Sometimes a diabetic injects too much insulin, which lets the cells suck up all the glucose in the blood. This will cause a major problem for brain cells, which need a continual supply of glucose in order to function. If there isn’t any glucose for them in the blood being supplied to the brain, the cells will start to “panic” and demand the body supply them with glucose right away! This is part of what is often called “insulin shock”. Diabetics, if they are fortunate, recognize the panic signal in time and try to get as much sugar into their bloodstream as fast as they can by eating sugar or drinking fruit juices or energy drinks that have a lot of sugar in them.
      (7 votes)
  • leaf green style avatar for user justin watkins
    what kind of damage would the sugar give to the body of not used? and to what extent?
    (4 votes)
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  • male robot hal style avatar for user jordog
    pm, what type of diabetes is more common, type 1 or type 2?
    (4 votes)
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    • hopper cool style avatar for user SpringyBeeps
      Type 2 is more common currently. But with modern technology people with type 1 can live as long as other people, provided they take care of themselves. (As opposed to 50 years ago, when people we're more likely to develop diabetic related diseases). So the numbers of people with type 1 may be growing. On the other hand type 2 can occur from unhealthy eating and obesity, which are becoming more and more frequent. So I don't know, they may be traveling proportionally.
      (2 votes)
  • leaf green style avatar for user Micky
    As I understood, the problem with Type 1 Diabetes is that their pancreas does not make insulin. What if the person got a transplant? With a healthy pancreas? Would it stop producing insulin despite having done so in the organ donor?
    (2 votes)
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    • leaf orange style avatar for user czduseklu
      This is a very bright question! There are indeed these transpantations running, but as it seems to me with epidemiology of the disease, this number will not be so high, to treat so many patients. Other information I've found (Medscape & Medline) by glance:
      - commonly is better to transplant both pancreas and kidneys, because high glycemia often results into the kidney failure and losing of albumine.
      - donors are from cadavers, and in that means it would be really hard to find a matching donor in a right time.
      - after transplant the pacients often reffer to have higher both quality and quantity of life. However, they need to use a big immunosupresive treatment in order to their grafts will not be rejected. This also means, that they are more likely to get any other infectious disease.
      - sadly, eventhough this cure would be really good for cope the Type 1 Diabetes the small number of donors and need of further pharmacological treatment makes this procedure to be as an alternative approach to delivering the insuline.

      Hopefully my answer will satisfy you. :-)
      (4 votes)
  • aqualine ultimate style avatar for user Metroid Apprentice
    I know what the receptors are made of,how do they work?
    (2 votes)
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  • leaf grey style avatar for user Darkranger919
    Can you cure either types of diebetes? if so, how?
    (3 votes)
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    • female robot grace style avatar for user Terri.Wells
      As I understand it, Type 1 diabetes can be cured with a pancreas transplant. Organ transplants carry certain risks, however, and they're very hard to get, so I believe those tend to be a last resort.

      As to Type 2 diabetes, I have seen some people claim to have cured it in themselves; also, I've heard of some very suggestive test results from people who've have an operation to reduce the size of their stomachs (which really shouldn't be connected to diabetes, right?).

      It is possible for someone diagnosed with Type 2 diabetes to get their blood sugar readings down to the level of a non-diabetic; it's even possible to get A1C readings (a test to check your blood sugar levels on average over three months) to the level of a non-diabetic. I've done it. But I don't consider myself cured; I consider myself to be in remission. If I stopped doing all the things that I've been doing to keep my blood sugar under control, I'm certain my sugars would go up again.

      As I understand it -- and I am not a medically trained person, just an educated layperson who's been living with Type 2 diabetes for about three years now -- diabetes is a progressive disease. Short of a pancreas transplant, we can't cure it -- yet. But we can slow down its progress quite a bit, depending on a number of factors, many (but not all) of them within a patient's own control. I hope that answers your question! :-)
      (2 votes)

Video transcript

Every cell in the human body needs energy to survive and do its different functions. If we're talking about a brain cell, it needs energy to keep stimulating other brain cells and sending on signals and messages. If it's a muscle cell, it needs energy to contract. They need energy just to do the basic functions of a cell. And the place that they get that energy from, or the primary source of that energy, is from glucose. Glucose is a simple sugar. If you were to actually taste glucose, it would taste sweet. And glucose gets delivered to cells through the bloodstream. So this right here, I'm drawing some blood that's passing by a cell. Maybe the blood is going in that direction over there. And inside the blood, let me draw some small glucose molecules passing by. And so in an ideal situation, when a cell needs energy, glucose will enter the cell. Unfortunately, it's not that simple for the great majority of cells in the human body. The glucose won't enter by itself. It needs the assistance of a hormone or a molecule called insulin. So let me label all of these. This right here is the glucose, and it needs insulin. So let me draw insulin as these magenta molecules right over here. That over there, that is insulin. And the surface of the cells, they have insulin receptors on them. And I'm just drawing very simplified versions of them, kind of a place where these magenta circles can attach, can bind. And what happens is, in order for the glucose to be taken up by the cell, insulin has to attach to these receptors, which unlocks the channels for glucose. In order for the glucose to go in, insulin has to bind to the insulin receptors. And then, once that happens, then the glucose can be taken up by the cell. Now, unfortunately, things don't always work as planned. So let me draw a couple of scenarios here. So, once again, let me draw my very simple version of a cell and let me draw the bloodstream going by right over here. And then let me draw the glucose in the bloodstream. So I have my glucose floating by, and then I have my insulin receptors on the surface of a cell. Now, the first thing that could go wrong here is what if the body does not produce insulin? Insulin is produced in the pancreas. What happens if the pancreas is not producing insulin properly? So no insulin. Well, in this situation, since there's nothing to bind to these receptors, the glucose channels won't be opened up, and the glucose will not be able to enter into the cell. And this situation is type 1 diabetes, where you've got glucose. So in theory, you have energy and you have properly-functioning insulin receptors, but you just don't have insulin to unlock the gates for the glucose-- for the glucose to actually go into the cell. The other scenario you could imagine happening-- let me draw the cell again. So there is my cell and let me draw the blood flowing past the cell. And once again, obviously, this is just one of trillions of cells in the human body. We have an estimated 10 to 100 trillion cells. So this is a very simple diagram, but, hopefully, it gets the point across. So once again, let me draw some glucose floating by. Let me draw some insulin receptors on the cell. Insulin receptor there, maybe an insulin receptor right over there. And let's say we even have some insulin. Our pancreas is producing insulin and putting it into our bloodstream. So it's there to be used. But a situation can arise where the receptors are not working properly or we become insensitive or desensitized to insulin. So in this situation-- sometimes maybe it might be the insulin is hard to bind or, even if it does bind, it's not working properly. So the glucose will not enter the cell. I already wrote desensitized. So in either one of these scenarios-- let's just think in a very broad level. I'm not going to go into the details of the actual therapy for these diseases of how it can be cured. Oh, and I didn't even name the second one. The second one right here, as you can imagine, if this up here is type 1 diabetes, this down here is type 2 diabetes. The simple way that-- I don't want to say that it's necessarily simple, but the way that you could manage type 1 diabetes is you can inject insulin. The only problem here-- it's a big one, though, is that there's no insulin in the bloodstream. Everything else is working properly. So over here, we can inject insulin. And then you'll have insulin to attach to the receptors, and then the glucose can be processed properly. Type 2 diabetes-- there's multiple lines of attack. One thing that you can do-- there are actually drugs that attempt to re-sensitize your insulin receptors. You can also do that with a combination of lifestyle changes that makes your body, I guess, more sensitized to sugar. Or you can even-- if things get severe enough, you can add insulin, just like you would do in type 1 diabetes. And you can say, wait, I already have insulin here. Why would I add more insulin? Well, remember, the cells can process insulin, but they're desensitized. They would need more insulin in order to uptake the same amount of glucose. So if you add insulin, you could possibly have enough of a trigger that the glucose can actually be taken up. But there's multiple lines of attack here, and usually the first one are giving drugs that help, hopefully, re-sensitize or make you less desensitized to the actual insulin. So the last thing I just want to think about a little bit is-- well, what happens if you didn't do this. Well, there's two major problems here. Obviously, your cells can't function if it's not taking up glucose. So your cells will have no energy. And another problem-- if you weren't to manage either one of these types of diabetes, is that sugar, if it gets to high enough concentrations in the blood, it can actually cause a lot of damage. Sugar can cause damage to the body. So you don't want either of these things happening. You want your cells to have energy, and you don't want to have too much sugar flowing in your blood and causing damage to your body.