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What does the liver do?

Dr Patricia Lalor explains the various functions of the liver
Hello, everyone. Welcome back to our course on liver disease. And today we’re going to use Dave again. But now we’re going to move on from talking about liver anatomy to actually consider some of the functions the liver has and how it copes with some of these challenges that you might present it with. So if you remember from the anatomy video that you’ve just seen– I’ll just take Dave’s liver out again, sorry Dave– we talked about how the liver was really intimately connected with your digestive organs. So this should give you a big clue to one of the major functions that it has, which is actually to help you with digestion and utilisation of your food materials.
So sugar is a good example of this. So if you have sugar in your diet from something like this apple, it will travel to your liver from your intestine and to the back of the liver. And then what the liver can actually do is store that sugar until you need it. So what it does is it converts the glucose into a polysaccharide called glycogen, which it can store overnight until there’s a situation where you may need that sugar, so where you’re sleeping and not eating. And it can gradually release that sugar, convert it back to glucose, and release it back into your bloodstream as you need it to help maintain your sugar levels in your blood.
So that sort of hints at a kind of digestive and storage function of the liver. And it’s also really good actually at storing other components that you might find here. So vitamins and minerals can also be stored in the liver. The other situation, you may not have such a good diet as this. You may have eaten too much fat. And the liver can actually use that fat as an energy source. So it can break it down and use the energy. But if you have too much fat, then you actually get a situation where the fat can be stored inside the hepatocytes.
And it forms a little sort of bubble of triglyceride, which again can be broken down and can be used for energy. But if that becomes too much of a problem, so if you have too much fat in your diet, and there’s an excess of lipid flying around, then you get something called fatty liver disease. And we’re going to hear about this a bit more, when we talked to a liver pathologist, Stefan Hubscher, but also when we talk to one of the physicians who treats liver disease later on. So minerals, vitamins, glucose can all be stored in the liver.
So if we then move on to think about another function of your liver– we talked about this also briefly in our first video. And this is to do with bile, which if you remember is stored in the gallbladder at the back of the liver. So one of the functions of bile is to help you cope with those fats, actually. So when you eat, your gallbladder will contract. And it squirts bile down into your small intestine to help you make that fat soluble, or at least emulsify it so that you can actually use it for food. The other thing people often talk about when they’re considering the liver is it’s actually something of a factory.
So it makes important proteins for the body. So a good example of this is the proteins that actually help your blood to clot. So they’re produced by those hepatocytes within the liver. And then they’re secreted into the circulation, out into the periphery. So if you get an injury or a wound, those factors are available to actually help your blood clot. And this is one of the reasons why patients with liver disease may have a bit of a challenge if they have to have surgery, or if they have to have a liver biopsy. Because obviously if their clotting is compromised, then that makes these procedures risky.
So liver physicians will always make sure that a patient is clotting properly before they would attempt surgery, for example.
So the next function we’ll talk about relates to these bottles of alcohol that we have here, but also these drugs that we have in front of us. So one of the major things your liver does to keep you healthy is it actually detoxifies chemicals that enter your system. So this could be alcohol you drink, a prescription medication that your clinician prescribed for you, or it could even be cosmetics that you put on your skin. Everything makes its way into the bloodstream and ends up in the liver. And then what the liver can do– again, in those hepatocytes, there are enzymes which can actually break down these chemicals.
They can either use something which is useful– so for example, calories from something like alcohol can be utilised. Anything else is broken down and converted into a form in which it can be excreted through your kidneys. So through that means, your liver protects your body from anything harmful that comes into it through this ability to actually detoxify chemicals. So to summarise what we’ve covered today, we’ve basically tried to illustrate the major functions of the liver for you. So we’ve talked about its role in digestion. We’ve talked about the fact that it can help you store important things, so vitamins and minerals, for example. We’ve shown you how actually one of its major roles is actually to detoxify chemicals.
And we’ve considered how all of these actually keep you healthy. But the next thing that we’re going to consider in our next exercise is actually one of the things which characteristically happens when your liver is not working properly. This is something you may have heard of called jaundice, which is where you actually get a very characteristic yellowing of the skin and the whites of the eyes. So our next exercise will actually explain to you what causes that and why it actually happens.
Your task: Watch this video in which Dr Patricia Lalor explains the various functions of the liver, from digestion to detoxification. See if you can connect some of the cell types we mentioned in earlier activities with the functions we describe here. Reflect on any new information or ideas and share your thoughts with other learners in the comments area.
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Liver Disease: Looking after Your Liver

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