Spleen – Secondary Lymphoid Organs (Nursing)

00:01 The next lymphoid organ that we're going to discuss is the spleen.

00:05 The spleen is a very blood-rich organ, about the size of a fist that's located on the left side of the abdominal cavity, just below the stomach.

00:17 Of the lymphoid organs, the spleen is going to be the largest.

00:22 It is served by the splenic arteries and vein, which enter and exit at the hilum of the spleen.

00:32 The spleen functions as a site of lymphocyte proliferation, as well as an immune surveillance, and response point.

00:42 It's also going to function to clean our blood of aged blood cells as well as platelets.

00:50 And it also uses macrophages to remove this debris from this area.

01:00 And so here is a depiction of the location of the spleen in relation to other organs in our abdominal cavity.

01:10 So the spleen also has a few other additional functions.

01:14 First, it's going to store the breakdown products of these red blood cells.

01:19 Remember, it's going to bring in these old aged blood cells.

01:23 And so it can use some of the stuff that is in there, such as the iron for later reuse.

01:31 Secondly, the spleen is going to store blood platelets and monocytes that are going to be released into the blood whenever they are needed.

01:40 Such as when you have an injury, or some type of inflammation or infection.

01:46 Also, the spleen may serve as a site of fetal erythrocyte production or the production of red blood cells in the fetus.

01:58 Like the lymph nodes, the spleen is also encased by a fibrous capsule and as another one of our encapsulated lymphoid organs.

02:08 Also like the lymph node, the spleen has Trabecula from the outside that kind of reach into the inner portion of the spleen Histologically, there are two main components.

02:22 We have the white pulp, which are going to surround the splenic artery and the inside of the spleen.

02:29 And this is going to be surrounded by the red pulp.

02:33 So interestingly, when you look at a section of the spleen, the white pulp kind of looks like a white island in a sea of red.

02:45 So the white pulp is going to be the site where immune function actually occurs.

02:51 It contains mostly lymphocytes that are found on reticular fibers, And the white pulp like I said, is going to cluster around the central arteries and appear as islands of white in a sea of red pulp.

03:07 The red pulp on the other hand is the site where those old blood cells and the bloodborne pathogens are going to be destroyed.

03:16 This area is very rich in red blood cells as well as macrophages that are going to engulf them.

03:23 It also contains splenic cords, which is a type of reticular tissue that separates the blood-filled splenic sinusoids, which are very similar to venous sinuses.