Blood Supply of the Liver (Nursing)

00:00 Hi, welcome to our video series on the liver. We're going to give you an introduction to the function and some dysfunction of the liver. Ready? Well, there's your liver. You notice it's a little bigger on the right than it is on the left, and you've got those 2 giant blood vessels behind it, the vena cava in blue and the aorta in red. Now, we're starting here at the very basics because we kind of want to help you understand where the liver fits in the rest of your body. Now, in your body, it's up here in the right upper quadrant, but let's talk about those blood vessels. They're amazing in what they do. Now, why is that a picture of the heart? Well, looking back at our original picture, we had vena cava and an aorta. These are the same blood vessels that are connected right to your heart. Remember the goal of your intravascular space is that they're continuous. Right, it all goes together. So, look at our drawing there.

01:02 there. You see the aorta. It's coming out of the left ventricle. Now, that's that giant big blood vessel. The left ventricle pumps blood out to the rest of the body through the aorta. The aorta travels down through your body, and a branch of it will go often to the liver. But let's talk about the vena cava. That's in the right atrium of your body. That's deoxygenated blood that's being returned to the right side of your heart or the right atrium. Because remember blood enters the right atrium, right ventricle, then up through to the lungs, back to the left atrium, left ventricle, and then out through the aorta. So, we're talking about these vessels in the lungs. These are just connections to those original big and massive vessels. Now, when it comes to the inferior vena cava, the vein, the giant vein that brings blood back to the heart, you've got an inferior vena cava and a superior vena cava. Now, the superior vena cava is bringing blood from your head, in your arms, and your upper body back to the heart, but the inferior vena cava is what we're going to focus on in the liver because that carries blood from the lower body back to the heart, and the inferior vena cava is what the liver empties into.

02:19 So, we've reviewed the major vessels in the heart, the aorta coming out of the left ventricle and the vena cava returning blood to the right atrium. Now, let's look at them in comparison to your liver. So, a branch of the aorta coming out of your left ventricle down by your liver, a branch of the main aorta is the hepatic artery. That brings fresh oxygenated blood to the liver but let's look at the inferior vena cava. From deep inside the liver, once the blood has been returned to the liver, then it goes through the liver, through a filtering process, and it drains back into the inferior vena cava to go back to the heart and the vascular system. Okay, so into the liver from the aorta and the hepatic arteries, out of the liver through the inferior vena cava. Now, there're some special blood supplies in the liver because it actually has another one that we call the portal vein, and it's along the bottom of the liver that's returning blood from your intestines. We'll talk a little more about that later, but for right now, I'd like you to draw in at the bottom of the liver, just draw another vessel and write the words "portal vein." So, let's talk about the intestine connection. That's what we were just referring to. Now, the liver does over 500 different processes, it has a part in it, but it plays a really central role in most of the metabolic processes in the body. You've got this group of veins, and they're called mesenteric veins. Now, they're all connected to your intestines and your colon, and they come together. So, think of it as coming up from your gut, all these mesenteric veins, they join together and that's what makes the portal vein. So, all the vessels, the blood vessels, the mesenteric vessels from your colon, your intestines, all join together into the portal vein. Now, what they're doing is bringing stuff back, and when I say stuff we're talking about medications or toxic substances or food or nutrients are traveling from your intestines back up to the liver. So, have you ever thought about when you eat something, it goes in your mouth, down your esophagus, into your stomach. And then how does it get to the liver to be processed? Well, it's these veins. The mesenteric veins bring the stuff, right, the medications that you take or the food that you eat and from your gut, breaks down, and travels back to the liver through those mesenteric veins where they all meet up and go through the portal vein. So, that's how things you take by mouth end up in your liver. Now, once these substances are delivered to the liver, remember they come from those mesenteric veins into the portal vein, once they're delivered to the liver, they're processed, they're stored or altered or detoxified. So, the liver decides what it does with each one of the different nutrients. It depends on what the body needs and what the stuff it's bringing back, and then the liver will make a decision. It will either pass it back into the blood or it will send it back to the bowel to be eliminated. So, that's how the liver is a major processing unit. Right? You eat something, you take a pill, it goes into your gut, it breaks it down, it sends it back to the liver through those mesenteric veins into the portal vein, now it enters the liver from the bottom of the liver. So, you've got the aorta bringing fresh oxygenated blood and you've got that portal vein bringing back the blood with toxins, but good things too, and nutrients and medications to the liver to be processed. So, that's one of the unique characteristics of the liver, is it has 2 blood supplies, 2 vessels that bring blood into it; the aorta, hepatic arteries, and the portal vein from the gut.