 Hey everybody, Dr. O, in this video we're going to talk about the liver. So the liver is the largest visceral organ of your body, which basically means it's the largest organ organ or solid organ. Technically the largest organ in your body would be your skin. But the liver is very, very important. We can't cover the hundreds of functions that it has in any one video. So we're going to talk primarily about the classes of functions that it has, but let's take a look at where it is here. It's resting right under the diaphragm in the upper right quadrant, and it's kind of been picked up here so you can see the back a little bit. But you do see behind it would be the gallbladder, and we'll talk about why they're intimately connected. The liver does weigh generally about three pounds, such a large organ. Some people would say it only has two lobes, but we're going to say it has four. So it has a really large right lobe and then a smaller left lobe. But on the back you do have what are called the caudate and quadrate lobes. So I want you to know the liver does have four lobes, but there's some argument about that. The right lobe is the biggest part. So the liver is really cool. It can be generated right. It can actually give somebody a part of your liver, and it can regenerate. Very few structures can regenerate like the liver can, so something makes it kind of special. So we'll look at it histologically in just a moment here, but when I think of the liver, the first thing you should think of is liver cells. They're called hepatocytes, and we'll talk about some of the functions those cells would do. And then the liver, because it's a solid organ, would also have basically reticular tissue would be the packing peanuts that fill it in. But another term that's very important for you to know, what's called the functional unit of the liver is actually going to be a liver lobule, and I'll show you one of them in just a moment. So remember that the functional unit of the liver is a liver lobule. Let's just talk about big picture about its functions, and then we'll look at some of the blood supply and those types of things. The three main categories of functions that the liver has is metabolic regulation, hematological regulation, and then the production of bile, which is the easiest one, I guess. So metabolic regulation, think about it has an impact on carbs, lipids, and fats. They try the liver's job, one of its many jobs is to keep your blood sugar stable. So if you have high blood sugar, it can take glucose and store it as glycogen. If you have low blood sugar, it can convert glycogen back into glucose. It can create fat out of carbohydrates, something called de novo lipogenesis. So if your glycogen stores are full, the liver can take extra glucose and turn it into fat. As far as lipids, same things. It can synthesize fats. It can turn one type of fat into another type of fat, you know, monoinsaturated fats can be saturated, this types of things. And then as far as proteins goes, it obviously can ship proteins for use, et cetera, et cetera. Another metabolic function would be the storage of vitamins and minerals, and again, we're not covering them all here, but the liver is a mineral storage depots. It stores a lot of iron and other minerals. It also stores your fat-civil vitamins, A, D, E, and K, as well as B12. So we don't think about that, but B12 is a water-civil vitamin, but it is stored. A healthy liver should be able to store up to five years worth of B12. So that's just kind of interesting. This is why, you know, as far as from a nutrient density standpoint, organ meats are considered the most nutrient-dense foods on the planet, and the liver is going to be way, way up there because it stores the nutrients, and I'm not saying the human liver, but it stores nutrients. Other animals' livers do just the same. Then lastly, we have bile production. So when you think of bile, you probably do think of the gallbladder, but the gallbladder just stores and concentrates bile. The liver is actually where it's going to be produced. Okay, let's go ahead and take a look here. So when you think of the blood-spot of the liver, it's kind of backwards because most of the blood coming to the liver is going to be coming through veins, and that's because the hepatic artery does feed the liver to keep it alive and well, just like other arteries go and feed your organs, but you have to remember that a massive amount of blood that's entering the liver is venous blood on its way back from the small intestine. So the liver gets the first crack at almost everything absorbed from your gut, and we're talking about the entire gastrointestinal tract all the way down to the very distal large intestine rectaminatus. That's going to be absorbed differently, but as far as all the food you eat and things you drink, they're going to be, so things that are absorbed in the stomach, like ibuprofen, alcohol, these types of things, they're going to be taken to the liver, things absorbed from the small intestine, large intestine, you name it. So the liver gets the first crack at almost everything, and the reason I say that is because remember that long fats and fat-civil vitamins are absorbed into your lymphatic system first, so the liver wants to see what's coming in your gut. That way it can recognize pathogens, it can inactivate toxins, it can store what needs to be stored, et cetera, et cetera. So most of the blood flowing through your liver is going to be flowing through what are called portal veins, so that's going to be the key difference between most organs. You think most organs, most of the blood is coming arterial blood, but the hepatic artery takes care of the liver itself. The portal veins are all this material coming in through your gastrointestinal tract to be filtered and cleansed and dealt with by the liver. So the liver can also, liver stores a lot of stuff too, so if the liver needs to release anything, it'll dump it in the blood supply, and that's going to be carried back with your venous blood, your hepatic vein, to your inferior vena cava, to your heart, and then it's going to go wherever it needs to go. So you can make this more complicated if you want to, but I think that's the key thing to understand here. We've already talked about the hepatocytes being the key cell of the liver. Here you do see one of those lobules, which I call the functional unit of the liver. Primarily about 80% of the cells here would be hepatocytes, but there also are going to be cells that produce and transport bile. And then we do have the sinusoids here. So we mentioned these back a few chapters ago, really large, wide open capillary beds are called sinusoids. They're going to be lined by immune cells to make sure that things coming through shouldn't be bad. And if you hear any other terminology here, I guess the last thing I would say, as you can see it on the right hand side, a portal triad would be a branch of the hepatic artery, you see an arterial there, a branch of the portal vein, and one of these bile ducts would be what's called the portal triad. All right, so the function of bio, we talked about that, we can cover that more with the gallbladder as well. Why don't we actually go ahead and do that? This video is getting kind of long, and the gallbladder video is going to be shorter, so let me just cover the function of bile as far as emulsifying fats and et cetera, and we'll stay tuned for that in the video with the gallbladder. So I think that's plenty to know about the liver here for now. I hope this helps. Have a wonderful day. Be blessed.