okay let's talk about the lymphatic system this all-important system for immunity my endless talk at it in terms of looking at some pictures some PowerPoint of structures and at a structure list okay since this is a system and it is made up of organs then we see some of the structures involved and we see some repeating names like lymph nodes it's just that we need to know what is the body area that these lymph nodes are in are they in the groin so the inguinal lymph nodes would be in the groin or the in the armpit area so X Larry lymph node to being an excellent area so in reality we don't have a big structure list like we do for a lot of systems but we have a lot going on in the structures that we're talking about so looking at our structure list notice it's a fairly short list here we have lymphatic capillaries lymphatic vessels cisterna chyli thoracic duct right lymphatic duct lymph nodes tonsils and we have three types of tonsils spleen thymus gland and then something that's often referred to as malt which is mal t mucosa affiliated lymphoid tissue and then part of that malt is something that we call peyer's patches also known as aggregate lymphoid nodules so we're gonna kind of run down through this list and look at them talk a little bit about each of these structures first structures we are going to look at is going to be the lymphatic vessels and we're going to talk about the lymphatic vessels and the lymph nodes and then we'll talk about the lymphatic capillaries and the thoracic duct and the right lymphatic duct so again looking at this picture and now noticing that we have these lymphatic vessels also known as lymphatic so all these kind of green things which they're really not green but they're very very similar to veins so you don't confuse them with a vein then they make them green instead of blue okay but they're very structurally very similar to veins and they transport we know veins transfer blood we know arteries and veins sport life so lymphatics transport a fluid that's derived from blood and we call that fluid lymph so I've got these literally more lymphatics or lymphatic vessels I have more of those than I actually have veins in my body but most people aren't even aware that they have it now dispersed and attached to the lymphatics all throughout the body but especially aggregating in certain regions we have lymph nodes and so most of us have probably known we've had lymph nodes for quite a while even though we might not have realized that we had lymphatics or lymphatic vessels but the lymph nodes so most of us realized that we had some lymph nodes in our neck because at some point in our life we probably had a sore throat where our lymph nodes and our neck swelled up but we literally have them all over our body it's just that we do have them kind of gathered in specific areas so if you notice lumbar lymph nodes are going to be lymph nodes in the lower back region cervical lymph nodes are going to be lymph nodes in the neck region axillary lymph nodes lymph nodes in the arm pit region and so forth but notice we do have lymph nodes scattered throughout the whole body now let's talk about the lymphatics or the or the lymphatic vessels well just like our blood vessels branch down and form blood capillaries than our lymphatic vessels also have lymphatic capillaries now our blood is a closed system meaning that the arteries are connected to the veins with capillaries and everything's connected to the heart therefore we can circulate oxygenated blood through our arteries what would be called our systemic arteries and then we can exchange materials from the blood at the capillaries into the tissues so ourselves and tissues here are receiving the contents of blood you can see the arrows represent the content of blood you know seeping out of the capillaries into the tissues to take the tissues the oxygen the glucose amino acids all the things the all the things that the tissues need okay and then the blood you know picks up carbon dioxide and waste materials and goes into the veins and we of course the systemic veins start out as something called venules and they go back to the heart so we call the blood a closed system but notice the lymphatics the lymphatic capillaries are not attached to something else instead they receive fluid that has actually started out as plasma and escaped and became interstitial fluid and then some of that interstitial fluid actually went back into the blood but not all of it did so where did the excess interstitial fluid go well it went into the lymphatic capillaries it became a fluid that we call lymph and then it is also going to the lymph is going to actually go back to the bloodstream before it enters the heart so just like the blood from the arteries are blood going away from the heart veins or blood that's going towards the heart well just like the venous blood the systemic venous blood is delivering blood back to the heart then the lymphatics are delivering the lymph that was actually derived from the blood back to the heart so again the fluid portion of the blood called plasma leaks out around the tissues around the cells and that fluid now becomes interstitial fluid some of that interstitial fluid goes back into the blood some of it stays around the cells and some of it actually goes into the lymphatic capillaries where it becomes lymph and then it's going to be squeezed back towards the heart now again here's a systemic artery here's a systemic vein and here is my lymphatic vessels and notice that my lymphatic vessels actually have valves we know that veins have valves arteries don't have valves so again the arteries have blood pressure pushing blood through it but the veins and lymphatics actually have to have external pressure pressing against it such as our muscles to squeeze the lymph back towards the heart so the vainest blood would be going this way towards the heart and the limp that's actually going towards the heart we're empty back into the veins before it goes into the heart here we actually see a lymphatic vessel notice in reality it's not green but we can literally see a valve inside of it of course valve stop backflow so no Southend the lymphatic vessel is it's structured much more like a vein arteries have very thick walls because they have a lot of blood pressure inside of them okay now where is the lymph being squeezed well once it enters the capillaries then it runs through the lymphatic vessels and eventually it goes to two places okay notice here is our vena system right here there's a brachiocephalic vein brachiocephalic vein this is actually a jugular vein this is a jugular vein and this is a subclavian vein so right at the junction of the jugular and the subclavian before it goes into the brachiocephalic vein the lymph enters into what's called the thoracic duct in the thoracic duct runs all the way up the thorax and empties into that Junction and then over here we've got the right lymphatic duct so I actually have two places that are minting limp back into the blood before the blood enters back into the heart because the brachiocephalic send the blood back to the spirit vena cave and we know that attaches to the heart so this fluid that derived from the blood I put back into the blood before going back into the heart now notice this picture right here notice how I've got this it says drainage of the right lymphatic duct drainage of the thoracic duct because that's the right lymphatic duct that's the thoracic duct so what the pictures telling me is that all of the limp below the diaphragm and on the left side of my body empties into the thoracic duct all the lymph above the diaphragm but on the right side of my body empties into the right lymphatic duct and that's often why we see something that looks like this whenever we see a representation of the lymphatic system you'll usually see a model or a picture with one of the arms up and the other arm down what they're really trying to show you is that the body is not symmetrical as far as where the lymph empty so remember everything below the diaphragm and on the left side of the body empties into the thoracic conduct which here we see the thoracic duct right there remember that's at that junction of the the subclavian and the jugular vein but everything above the diaphragm on the right side of the body if he's back into the empties the lymph back into the blood on there into the right lymphatic duct and of course that's the right subclavian and the right jugular vein so again we've got these two places that were emptying the lymph back into the body and and so we need to understand the symmetry of that and again that's why the picture is represented like it is now everything that's actually going into the lymphatic duct has to come to this cistern here this enlarged area that has several several lymphatics running into it and it's at the base of the thoracic duct and that's this area called the cisterna you'll hear it pronounced different ways chili Kyle I I like to go let's cisterna chyli because it just helps me remember the name better to actually make it sound like a name so again you'll hear different pronunciations of that but cisterna chyli is this enlarged area that is actually at the base of the thoracic duct so everything below the diaphragm is basically emptying into the cisterna chyli as it becomes the thoracic duct and empties back into the bloodstream okay so now hopefully we know what the lymphatic vessels are we know that lymphatic capillaries are what initially brings the lymph into the lymphatic vessels it's just the smaller portion of the lymphatic vessels we know that the lymphatic vessels empty into two places that thoracic duct and the right lymphatic duct we know that the Resik duct has a large area at the base of it called the since cisterna chyli okay and the other thing that we want to talk about right now is that as the lymphatic vessels are carrying lymph towards these areas the lymph passes through these little nodules called lymph nodes so again we can see the lymph nodes scattered all throughout the body and Limp is going to pass through the lymph nodes on its route back up to be empty back into the blood now so what's the purpose of the lymph nodes well we know that the lymphatic system has a lot to do if immunity so the lymph nodes are really important in immunity okay here are see a structure of a lymph node I have several what's called a ferrant vessels which are bringing lymph towards the lymph node and one efferent vessel that allows lymph to leap the lymph node now as the lymph goes through here what it's doing it's actually bringing invaders or bringing our white blood cells called antigen presenting cells to the lymph nodes because in the left nodes we literally have some immune cells called B cells and T cells which do specific immunity and that's a whole other subject okay but they do specific immunity but we have to activate the cells that do specific immunity to get them ready to go fight the infection so how do we activate them because they tend to hang out in the lymph nodes now it doesn't mean they're in the lymph node all the time but they do tend to hang out there for periods of time so it's easiest for us to find a b-cell or T cell that recognizes the invading pathogen or was also what's called an antigen and to activate it to activate our immune system we send either a cell that's already come across the invader or the invader itself into the lymph node activate the B cells and T cells against it the B cells actually produce antibodies and the T cells actually become activated and go kill cells that are infected with infections especially viruses now that's a whole subject going but the lymph nodes are kind of like guard towers where the soldiers hang out until they're activated to go fight the enemy okay we have some specific lymph nodes that are called tonsils and these are there's actually three pair of tonsils now when somebody says have you had your tonsils out most of time they're talking about the Palatine tonsils if you've ever heard the term adenoids those are actually called pharyngeal tonsils and they're in your upper respiratory area and your Palatine tonsils in the back your throat and then one that most people are familiar with are called lingual tonsils and they're at the base of your tongue but what these are these are actually lymph nodes that do not have a capsule surrounding them but they're actually exposed to the open air that's coming in through your nose or through your mouth and so if any bacteria or viruses or whatever come through here the bacterial viruses tend to get trapped in these crypts and that activates those white blood cells here that are ready to kill whatever got exposed and of course when we do get exposed and we're activating those that's when these things tend to swell up because inflammation is part of the process of activating these