Anatomy of the Lymph Nodes (Nursing)

00:01 Station all throughout these lymphatic vessels ready to sort of sample and respond to any sort of dangerous bacteria or virus or fungus are the lymph nodes.

00:16 And so these lymph nodes are constantly sampling the lymph fluid as it's flowing through them.

00:23 And they're located throughout the body in various areas such as the cervical lymph nodes of the neck, axillary lymph nodes in the armpit area, thoracic lymph nodes in the area of the chests, we have intestinal lymph nodes.

00:38 And these all make sense because the lungs and the intestines are basically exposed to the outside world.

00:44 So there's going to be a lot of lymph nodes there.

00:46 Inguinal lymph nodes down in the pelvic area as well.

00:51 Now the typical appearance of a lymph node is going to have various afferent or afferent lymphatics, which are the lymphatic vessels coming into the lymph node through a very thick capsule relative to the size of the lymph node.

01:12 And there's gonna be a little space below the capsule called the subcapsular sinus where the lymphatic fluid is first going to enter.

01:19 It's going to go through the lymph node, do its sampling and see if it needs to respond to anything and eventually flow out of the lymph node via the efferent or efferent lymphatic down to the next lymph node in the chain.

01:33 And this location of the efferent lymphatic is also what will find the tiny little veins and arteries that supply the lymph node.

01:41 And just like a lot of other organs where there's one spot where arteries veins, and in this case, lymphatics enter, this is the hilum.

01:49 So again, just like the hilum of the spleen, or the hilum of the kidney or the hilum of the lung, this is where the blood vessels enter and exit.

01:56 And in this case, we also have where the efferent or efferent lymphatic travels.

02:03 Now, the lymph nodes, we typically think of it as sampling for things like, you know, bacteria or other infectious organisms.

02:12 But clinically, we can also use this to our advantage to help what we say stage things like cancer.

02:18 Because cancer cells can also travel through afferent lymphatic vessels to reach nearby lymph nodes.

02:26 And so when they do that, they can reach that subcapsular sinus and they can proliferate into that lymph node and become a metastasis, a very specific type called a lymphatic or lymph node metastasis.

02:41 And of course, because the lymphatics all eventually flow down to the venous system, cells can also exit a given lymph node via the efferent lymphatics, and travel down to the next lymph node in the chain.

02:56 This is also a spot where lymphatic fluid and blood vessels might be able to mix so this is also a potential area where cells can enter the blood.

03:06 And in this case, we call that hematogenous metastasis because it's flowing through the bloodstream.

03:13 And therefore it can spread to much greater distances than simply the lymphatics can.

03:20 So this leads us to the idea of something called a sentinel lymph node and a sentinel lymph node biopsy.

03:27 So for example, here we have a breast with a tumor, and we have the nearby axillary lymph nodes that might be draining this area.

03:38 And because we're in the right upper limb area, it would drain eventually through the right lymphatic duct to reach the junction of the jugular and subclavian veins on this side.

03:49 Now, if this is the location of the breast tumor, we would say the sentinel lymph nodes are whatever lymph nodes are the first lymph node along this lymphatic drainage after the breast tumor.

04:02 So in other words, if cells were to break off of this breast tumor, the sentinel lymph nodes are the first ones, those cells would reach in the chain.

04:14 And so what you can do is you can inject a radioactive dye in the area of the tumor to simulate where the cells might go.

04:24 So what you can do is use this radioactive dye to be taken up by the lymphatic vessels and find where those sentinel lymph nodes are.

04:33 So you can lose use a little Geiger device to see where they're being taken.

04:39 And then you can open up that area and look for those sentinel lymph nodes.

04:46 And when you do that, you can take them out and look and see if there's any cancer in them.

04:51 And if the sentinel lymph nodes don't have any cancer in them, you can be reasonably not 100%, but reasonably sure that subsequent lymph nodes in the chain won't have metastases either.