Anatomy of the Spleen (Nursing)

00:01 The next structure we're going to talk about in the hematologic system is the spleen.

00:08 Now, here we go into the abdomen so we can see the stomach, giving rise to the first part of the small intestine, which is the duodenum which is very closely associated with the pancreas because it receives the pancreatic duct here.

00:24 And just off to the left somewhat behind the stomach and hidden by it is a little bit of the spleen.

00:31 Now, the spleen is quite different from these other abdominal organs that pretty much all have something to do with digestion.

00:37 Of course, the spleen isn't really related to digestion, it's hematologic.

00:42 But if we were to fade out the stomach, we could see the spleen and its relationship to these structures much more clearly.

00:50 So again, here's the spleen.

00:52 And then we see that we have the abdominal aorta, and a branch of the abdominal aorta that we mentioned in the GI section called the celiac trunk.

01:02 And one of the branches of the celiac trunk is the splenic artery, which runs along the length of the pancreas until it reaches the tail of the pancreas that sits right up against the medial surface of the spleen.

01:17 And similarly, the splenic vein is going to follow that same course going along the backside of the pancreas until it reaches the portal vein.

01:29 Here's a more medial view.

01:30 So we can see the spleen a little bit better.

01:34 And again, like a lot of organs that are otherwise solid and just have one entry and exit point for vessels, there's hilum.

01:43 And so the splenic hilum, is on the medial surface, basically facing the tail end of the tail of the pancreas.

01:51 And again, that's where we're going to have the splenic artery entering, the splenic vein exiting.

02:00 Again, we have the artery and vein entering the hilum.

02:04 And it's going to branch into many smaller and smaller blood vessels.

02:09 And all of these blood vessels and products inside the spleen are going to be held in by a very thin capsule.

02:16 And that's going to be important, we talk about pathology of the spleen.

02:20 And the spleen really serves two functions.

02:23 And it has two different components for these two different functions.

02:27 The smaller component by volume is something called the white pulp.

02:31 And that has an immunologic function, it's going to be composed mostly of white blood cells.

02:37 The majority of this means can be composed of the red pulp, and that's going to serve the hematologic function of the spleen.

02:46 So let's take a look at this hematologic role of the red pulp.

02:50 The bone marrow is making new red blood cells more or less continually.

02:56 That's because the red blood cells lacking a nucleus aren't going to divide into more red blood cells.

03:03 In fact, they only have a lifespan in the circulation of about 120 days.

03:09 And as they're circulating through the body, they're going through the spleen, and basically getting checked to see if they're still viable and should be long in circulation, because they're still functional, in which case, they can go back until they're not.

03:24 Or if they're too old, or they're damaged, then the spleen is going to take them out of circulation by phagocytosing them with those special cell eaters called macrophages.

03:38 Here we have a posterior view of how the spleen sits in the body.

03:44 So we sort of faded out the skin a little bit to see a little bit of the ribcage here.

03:49 And the spleen sits roughly between ribs 9 and 11 under the unusual circumstances.

03:56 And that's a really good thing because the spleen, as we mentioned, has a very thin capsule and it's full of blood.

04:02 So this protection, if you will of the ribs is pretty important.

04:08 Unfortunately, there are many conditions, such as various leukemias or infections such as mono that you may have heard about an Epstein-Barr virus infection, that can cause the spleen to become much more enlarged something called splenomegaly.

04:27 And when it gets enlarged, it can now extend beyond the protection of the ribcage.

04:34 And now it's out into the abdomen where there's no bony protection.

04:40 And that's important, because the capsule being so thin makes it prone to rupture.

04:46 And that's why if you've ever heard about someone who's had mono or you've had it yourself, you've been told you're not supposed to participate in contact sports for, you know, two to four weeks.

04:57 This is why.

04:58 Because now this enlarge arch spleen, in addition to being under pressure from the enlargement is also now dipping below the protection of the ribcage and makes it much more prone to rupture.

05:11 And unfortunately because the capsule is so thin, usually when it ruptures the spleen needs to be taken out altogether in a process called a splenectomy.