Anatomy of the Liver (Nursing)

00:01 Now let's take a look at some of the organs that help aid in digestion and attached to the GI tract.

00:09 We'll start with the liver, which carries out many, many other functions besides digestive ones, but we're going to focus on the digestive efforts here.

00:19 The liver occupies the majority of the right upper quadrant of the abdomen, but it's so big that it actually crosses over the midline and forms some of the left upper quadrant as well.

00:29 It sits just below the diaphragm.

00:32 Because it's such a large organ, it actually causes the right dome of the diaphragm to sit a little bit higher than the left dome.

00:41 Here we see the liver from an anterior view.

00:44 And the first thing we noticed coming off the inferior edge is this round ligament of the liver or ligamentum teres.

00:52 Teres just means round.

00:55 And that round ligament would actually attach all the way down to where the umbilicus or belly button is.

01:02 And that's because the round ligament of the liver is the obliterated remnants of the umbilical vein that once connected to the umbilical cord, and placenta.

01:16 If we look at the inferior border of the liver, just a little bit of the gallbladder is peeking out at us here.

01:22 But we're going to have to take a different view than the anterior view to see it more fully.

01:29 The liver has many ways of being divided.

01:32 And there are some complicated methods based on how blood flows within it.

01:37 But there's also a more basic way of just talking about the lobes.

01:41 For example, we're in talk about the right lobe of the liver, and the somewhat smaller left lobe of the liver.

01:48 And we can see that the right and left lobes are separated by another piece of connective tissue continuous with this round ligament, and it's called the falciform ligament.

01:58 And this ligament is essentially the surface of the liver or visceral peritoneum coming off and connecting to the anterior abdominal wall and its surrounding parietal peritoneum.

02:13 Superiorly, there's another sort of ligament that serves a similar function, the coronary ligament, except it's attaching to the undersurface of the diaphragm.

02:25 If we come around to an inferior view, we see a lot more structures though.

02:30 For example, we can now really see the gallbladder completely.

02:34 And we also have this little groove here and that's the fissure where the ligamentum teres around ligament of the liver would have continued from where we saw it in the last image.

02:47 And we can see that between these two, we have another lobe called the quadrat lobe.

02:54 And if we go more posteriorly we find some more structures.

02:58 Here we see the inferior vena cava on its way up to pass through the diaphragm and reach the right side of the heart.

03:06 Then we have another group or fissure and this one is the fissure for something called the ligamentum venosum, something that is also an embryo logical remnant of something called the ductus venosus.

03:18 And between that and the IVC, or inferior vena cava, we have our fourth lobe called the caudate lobe.

03:26 Then in between all of these lobes, we have this really important area called the Porta hepatis.

03:35 So this porta hepatis has a lot of important structures here.

03:39 So we see hepatic bile ducts.

03:42 One of the important things the liver does is produce bile which aids in the digestion of fats.

03:48 Then we also have vessels such as the hepatic arteries, and the portal hepatic veins or hepatic portal veins.

03:57 And that word portal is an important distinction when we talk about blood flow in the liver.

04:04 Now, it's a little confusing because the artery and the vein are actually both going into the liver and the bile is flowing out.

04:15 There's another set of veins leaving the liver that we just haven't seen yet.

04:21 So let's talk about the vascular composition of the liver.

04:26 So we have the hepatic artery proper, which is actually only carrying about 30% of the blood volume into the liver.

04:35 The other 70% is actually coming from the portal hepatic vein.

04:41 And this is different than pretty much any other organ you've learned about and that's because the portal hepatic vein, part of something called portal circulation.

04:49 So a portal circulation is where veins actually go through another set of capillaries before becoming a second set of veins as we'll see.

04:59 And so what these veins are, are essentially where the drainage of the GI tract is going.

05:05 So, for example, you're absorbing things in your small intestine.

05:09 Well, they're going to go through the liver first for processing before reaching systemic circulation.

05:16 And so that's what all this portal hepatic vein is.

05:19 Is this nutrient rich blood that's going to the liver for essentially a first pass it things before going into the regular bloodstream.

05:29 After that portal vein blood goes through the liver and is processed, including detoxification of anything like drugs or other sorts of toxins, then it will go into hepatic veins.

05:44 And those are veins that are going to exit the liver, head towards the IVC and the rest of systemic circulation.