this lecture we'll be going over the lymphatic system so what is the lymphatic system the lymphatic system consists of a fluid that is called lymph now lymph in and of its fluid is a clear pale yellowish fluid how lympha Rises is that as uh your blood flows to your blood vessels there is going to be fluid in your blood vessels that will get out of your capillaries and move into the space called the interstital space about 15% of your fluid gets into this space and it's not going to be able to be reabsorbed back into your blood capillaries it only ends up being about 3 liters a day but you don't urinate out those 3 lers a day so what happens is that those three lers actually eventually get returned back to your capillaries but you have to have a lymphatic system as kind of an overflow space throughout your whole day to maintain your adequate blood volume the fluid doesn't require um energy to move so it moves very passively from that high to low gradient and once it's gets inside the lymph vessels it's going to simply be called lymph so there's not much difference in the composition of what is lymph and what is found in your inner Cal space so it makes it very easy to move back and forth in lymph we find a wide variety of items we find water we find some small amount of pro proteins we can find some items that need to be destroyed such as old decrepit cells pathogens U metastasized cancer we know can travel through the lymph fluid it's also where we find large amounts of lymphocytes lymphocytes are one of your five types of white blood cells and white blood cells are your body's Army and so lymphocytes function to protect your body from anything that could be harmful here are the three main functions of the lymphatic system the first thing is that it's going to drain that extra interstial fluid from the tissue and then eventually return it back to the blood you would not be able to maintain your blood volume without the lymphatic system because you need a space in which the fluid can flow into it necessary um to be able to accommodate overflow but also to extract fluid from a place inside your body when your blood needs it second main function is to transport dietary facts we touch on this when we get to the digestive system but what you'll find out is that in the digestive system fats are too large to be transported in the blood so therefore the only way that they can eventually get to the blood when they are in your body is that they will be absorbed in the small intestine in lymphatic system and because your lymphatic system eventually connects to the blood fats will eventually end up in the blood but initially they're too large for your small intestine to absorb them and then the third main function is that's going to be carrying out immune responses by filtering the fluid as it goes through the lymphatic system and allowing your lymphocytes um to respond to anything that is not supposed to be inside your body so here's a picture from your textbook showing you a schematic illustration of the lymphatic system now note that in the picture as well as in models it is green but the fluid itself is not green it would just be hard to to pick a clear kind of pale yellow color which is why green is chosen white could potentially be an option but typically white is reserved for identifying nerves so I assure you that the fluid is not green it's just showing you in this image what it looks like if you were to put a green dye throughout the body in general the lymphatic system layout Begins by having a progressive sequence of extremely small vessels or structures and working its way to much larger vessels or structures so in general it's going to begin with lymphatic capillaries many lymphatic capillaries will merge together to form lymphatic vessels many lymphatic vessels will merge together to form lymphatic Trunks and then many lymphatic trunks will merge together to form lymphatic duct so it's kind of like little streams that eventually merge to form a raging River where you find the lymphatic vessels is that some of them are found in the subcutaneous layer of your skin so kind of through um the subq layer and other times it's going to be deep running near your organs and or near your arteries and veins it's just a very common place for them as well so they are both considered to be superficial and deep in their vessel Network When We Begin by looking at lymphatic capillaries what we see in the images down below is again that the green is going to be representing lymphatic fluid even though lymphatic fluid is not actually green but a huge difference between the lymphatic system in your circulatory system is that the circulatory system which is your blood the reason it's called circulatory because it's constantly cycling it's circular it never there's not a beginning and an end when it comes to your blood this is contrastly different because in your lymphatic system there is a beginning and there is an end the beginning is at lymphatic capillaries so they are closed on one end because this is where they're going to begin so down here in the picture you can see that right there is the beginning of a capillary and over here is when it's even more magnified to show you that this is a closed end so the closed end of the capillary is going to mean this is where it begins and its position amongst all of the cells here if you recall from a& P1 if the fluid is found inside the cell it is called intracellular fluid if the fluid is found outside the cell it is called extracellular fluid and then the extracellular fluid had two divisions you had the interstitial fluid and you had the plasma the interstitial fluid is going to be the fluid between the cells the plasma specifically the fluid in the blood so interstial fluid is what we see here in between the cells and you can see based upon the arrow that that fluid is working its way into this green structure of that lymphatic capillary again that means that it's going to be absorbing an interstial fluid so there's not a whole lot of difference in the composition between lymph and intertial fluid but it's an overflow space so that fluid can move into lymphatic tissue and then your body can get it if it needs to when you are needing extra fluid so those tiny little capillaries then are going to merge together to form larger lymphatic vessels another piece with this movement from capillaries to vessels is that lymph Moves In One Direction you can see over here on the left side that the arrows mean that they are going in One Direction so that ensures a one-way flow of fluid through the lymphatic system inside your small intestine the lymphatic structures there are called Lacs Lacs are specifically for transporting lipids and so it is a structure in the small intestine because when your body is absorbing your nutrients from the food that you eat fats are too large in your small intestine to get into the bloodstream so they will first go into your lymphatic system and then your lymphatic system will eventually empty into the bloodring so then lymphatic capillaries are going to unite to form larger lymphatic vessels lymphatic vessels differ from capillaries because they are larger structured lymphatic system but they are very similar to your blood veins the difference is is that they have thinner walls which allows for more transportation across their walls they also have more valves but valves ensure a one-way movement so there's only a one-way flow of lymph fluid and then all along the lymphatic vessels are going to be lymph nodes and they occur at various intervals depending upon the location and so lymph nodes are kind of scattered along the lymphatic vessels found in the body so when the lymphatic vessels merge together they are going to form lymphatic trunks there are many lymphatic trunks found throughout the body and lymphatic trunks are going to merge together to form the largest lymph vessels called the Ducks there are two ducks the thoracic duck and the right lymphatic duck and I have upcoming slides to talk more about them so just to review the sequence of how all of this occurs is that in the lymphatic system where the fluid is going to originate from is going to be the blood capillaries now this is purple because blood capillaries have a mixture of oxygenated and deoxygenated blood so in red and blue mix this is what you get as The Color Purple so the blood capillaries here are going to drain extra fluid which will then move into the interstitial fluid interstitial fluid then will overflow or move into lymphatic capillaries lymphatic capillaries will move into lymphatic vessels and remember along lymphatic vessels there is the lymph nodes from there it will move into the lymph trunks then trunks will merge together to form the two lymphatic ducts and then eventually these ducks are going to empty into your bloodstream at what is called the subclavian veins so sub means below clavian refers to clavicle so you have a vein that runs under each side of your body underneath the clav and this is where lymph fluid is going to drain into so you can see in this image here that we have um blue to represent veins and green to represent the lymphatic so it's an illustration showing you how these vessels are going to empty in so the two large structures of the Ducks are going to empty into the bloodstream so we have the thoracic duck this long wanting run back here the thoracic duct is going to empty into the subclavian Vein on the left side so up over here and I'll have a picture on the next slide that's even more magnified where we have the right duct is going to be draining fluid from over here So eventually the fluid will dump right here into the right subclavian vein so as I stated your fluid from your lymphatic system does eventually end up in your bloodstream so everything that lymphatic system is transporting it will eventually get to your blood so again just to clarify so here we have the blue to represent the veins the green to represents the lymphatic system on the left side the thoracic duct right here is emptying into the subclavian Vein on the right side we have the right lymphatic duct and that is going to be emptying into the right subclavian vein and so this is where those two big ducks are going to be emptying into the blood vessels to show you a basic schematic then about how this works to reiterate is that here's a capillary bed in purple here's another capillary bed in purple capillary beds are found throughout the body so this makes it look like it's only found the lungs in the one spot outside of that but within the capillary bed is where we see the beginning of the lymphatic capillaries lymphatic capillaries then will merge together to form lymphatic vessels and then the vessels will have lymph nodes scattered around the vessels and then the vessels are going to merge together to form your thoracic or thoracic your Trunks and then eventually the trunks are going to merge together to form your lymphatic ducts which will empty into the vein so again differences between your lymphatic system and your blood or your circulatory system lymphatic system is a beginning and an end it begins in capillary beds it ends when it dumps into your subclavian veins the fluid is lymphatic fluid which is very similar to your interstial fluid that is different than your plasma even though most of it comes from your plasma so to differentiate the two large ducts of the body we have the right lymphatic duct and then the thoracic duct so the right lymphatic duct is going to be draining the limp from the right side of the head in the neck the right Upper Limb and then the right side of the thorax the image on the right shows you based upon this line roughly where the right lymphatic duck is going to be draining and again this is going to empty into your subclavian vein which is right here draining just the upper right side of your face face your right arm and the upper right part of your thoracic cavity so it's the smaller of the two ducks the larger of the two ducts is the thoracic duct and the thoracic duct as you can see in the green drains everywhere else inside the body and so it's going to be draining the left side of the head down the left arm thoracic cavity and then everything below that so from the lower limbs in the abdomen this is the large of the two and it will empty into the left sub Ian vein if you were asked a test question as far as where does the lymph fluid from your right thumb drain you would say the right lymphatic duct if I were to ask you where your left ear drains you would say thoracic duct so you need to know the difference as to where that fluid is going to end up based upon where it drains a clinical connection at this point is in regards the condition called lymphadema lymphadema has the prefix lymph and a is usually means swollen or retaining tissue so this means that you are specifically holding on to lymphatic tissue when this happens is that you get too much fluid in that interstitial space and that's because for whatever reason it's not draining into the lymphatic tissue when this occurs it typically will put pressure on the structures that are in that place where it's swollen and occasionally because there's too much fluid in there it can can slow down wound healing as well as maybe cause infection in that area often times lymphadema is caused by some sort of blockage of the lymph vessels so this means that perhaps the lymph vessels have been removed because of a trauma to it or some injury so cutting it off basically the river or it could be due to a scar setting in from some sort of surgery or radiation and then when surgery for example in can removes lymph nodes you are missing lymphatic vessels so that creates a blockage of your lymphatic vessels in lymphadema it can occur we see it mainly affected in the limbs B lymphadema can help be treated with people wearing compression stockings exercising and lymphodema massages but some people will have it permanently because of again some sort of cancer or radiation or trauma that has blocked the blood vessels and there's not much that can be done so here's two images to show you particularly the two at the top in regards to examples of lymphadema so you can see what's happening here in the lymphadema is that the fluid has been swelling you can see in this one around the ankles about around the feet so this is where the fluid is found at is in the lymph and then the picture on the right we can see the individual here has her left arm that is demonstrating lymphadema so it can be found in very profound in your limbs down below is a very significant case of lymphadema called elephantitis and elephantitis is a very very Advanced situation when it comes to lymphadema in addition to the lymphatic vessels capillaries trunks we also inside the body have what's considered to be primary lymphatic organs and secondary lymphatic organs primary lymphatic organs are the place where the body is producing uh imuno cells and these become more mature so they become immunocompetent meaning mature immunity cells and once they do that then they are able to have or direct an immune response the two primary lymphatic organs are the red bone marrow and the thymus we will talk about the red bone marrow when we get to the blood system as well so it's a dual organ and then we talked about the thymus gland in the endocrine system what the red bone marrow does in general for your lymphatic system is it's going to be responsible for having the capacity to produce new B cells and te- cells which are white blood cells found in your blood and so these cells come from the red bone marrow and then the thymus gland is going to be where you are storing te- cells and they will be be released when you need them for an immune response the red bone marrow then as the name describes is found within bones and it's red in color that's why it's called that particularly it's in the part of the bone that's considered to be the spongy bone red bone marrow is responsible for hopis which is the production of all components of the blood so the components of the blood would be red blood cells white blood cells and platelets that comes from red bone marrow so one of the pieces that's part of the lymphatic system is that within the white blood cells you are going to be producing lymphocytes lymphocytes is one of the five white blood cells so we have one two three four and then the two lymphocytes here is the fifth type and again we talk about this when we get to the blood chapter the two divisions of the lymphocytes the big major divisions are what's called t lymphocytes and B lymphocytes they play a role in your body to fight off infection because they are part of your body's our immune response and this is also talked about at length when we get to the immunity division chapter here as part the division of chapter 22 of the immunity so then the second primary lymphatic organ is going to be the thymus remember the thymus is also talked about in the endocrine system because the thymus is essentially a gland that can produce some hormones um to help assist the body to protect it the thymus is located in your thoracic cavity anterior to your heart it's biobed and its main thing is that it's going to be a place where tea lymphocytes can grow to become mature so they hang out in there and they get to grow to the point where they become immunocompetent in children we find the thymus gland to be quite large because of the activity that it does for the body of making sure you will have adequate production of T lymphocytes to protect a child and a child essentially is immunosuppressed when you were born because you haven't stretched your immune system but as you age when your immune system gets stretched and stronger the thymus gland is no longer needed in abundance so therefore it begins to regress and becomes more adapost tissue as you become an adult and and basically get much smaller before it begins to atrophy or get smaller it will populate the secondary lymphatic organs that we talk about next with the tea cells so what's working when you are a child to get enough tea cells in your body to store them elsewhere when the thymus gland regresses so there are three secondary lymphatic organs and or tissues the three are the lymph nodes the spleen and lymphatic nodules remember the two primary lymphatic organs were red bone marrow and thymus and the purpose of those is to support the lymphatic cells to become imuno competent so that they can have a immunity response where where the immunity response can occur then is in these secondary lymphatic organs so the first one is looking at lymph nodes you probably are familiar with the superficial lymph noes or the lymph noes that you can feel for example along your neck or in your armpit along the groin Li noes are small they kind of feel like a little bit of a bean you have roughly about 600 that are positioned both deep and superficially superficially again means through basically the subcutaneous layer you can feel them right along the your jaw you can feel them along your neck sometimes in your armpits and groin you can feel them as well the ones that are deep are surrounding organs inside your body and so therefore it's hard to get to them because you'd have to cut inside the body remember that lymph nnes are located along the pathway of vessels so how it happens is we have a lymphatic vessel and then a lymph node another lymphatic vessel a lymph node another lymphatic vessel and then a lymph node so there could be many many in a row the purpose of this is that all along those lymph vessels the fluid gets filtered as it passes through your lymph nodes and so the lymph nodes will remove anything that is not wanted and within the lymph nodes your body can mount a immuno response by attacking and getting rid of anything that doesn't belong So within your lymph nodes we find cells that are called macroasia macras are able to remove anything that is dead or decrepit or anything that's foreign and anything that's dead or decrepit eventually can get trapped in the lymph nodes themselves and the lymph nodes will then help to destroy them so it's also helpful because they're Chained and linked together so your fluid has to go through multiple lymph nodes as it gets filtered because the very first lymph node over here isn't going to catch everything and that last lymph node here can and so lymph nodes work to help to filter and protect the body from anything that doesn't belong again you find them in clusters found in different body regions so the ones that are located the armpit that are linked together are called the axillary and the ones that are located in your groin are called the inguinal here's a very magnified image of a lymph node with a illustration so over here we see the lymph atic vessels bringing fluid into this lymph node and then on the opposite side we see other vessels making sure that the fluid Flows In One Direction within the tissue of the lymph node we again are going to see macras and macroasia are going to be your um cells that going to eat debris as it filters through here all of the lymph nodes then are linked together which helps to filter out that fluid as it gets through the lymph node if we look at the tissue on the left side of lymph fluid or lymph fluid of lymph tissue it looks very um glandular and it is uh but it's going to contain lots of macroasia and white blood cells to destroy anything that doesn't belong and then on the right side is an image of a lymph node laying on top of muscle and a nerve and you can see all of these structures kind of looks like a spiderweb connecting through it you have some that are bringing fluid to the lymph nose those are your aarant vessels and then you have some that are taking the fluid away from your lymph node after it has been cleaned and those are the your eent you probably are familiar that when your body detects a foreign substance or something that doesn't belong the lymphocytes inside your lymph nodes can generate an immune response so if it filters to your lymph nodes your lymph nodes then will be stimulated to cause your white blood cells in this case lymphocytes your part of your white blood cells and they will go through cell division to produce more lymphocytes some of them will stay in that lymph node to destroy that foreign body others of them will move into the bloodstream and then the blood will deliver them where they need to go to again help to fight off the infection so therefore when your lymph nodes are swollen it indicates that your body is fighting off something and you can usually feel the swollen lymph GES that that's one of the things that if you visit a doctor and you are sick they're going to feel forward and make sure that your body like to double check that that's what's actually happening in your body you can't tell the difference between a virus and a bacteria foreign substance at this point because your lymph nodes are going to respond no matter what it is so a second secondary lymphatic organ is the spleen the spleen is the largest of all the lymphatic organs and it is positioned in your upper left abdominal quadrant so it's below the diaphragm but it's in kind of the upper posterior part kind of right to the left of your stomach going into the spleen is going to be a space called the hilum and the hilum is going to be found on many organs and the hilum basically just describes where structures enter and exit so the hilum is where the blood vessels and nerves are going to enter in this case into the spleen so you can see that they have a one location the spleenic artery and spenic vein that they are entering and exiting you don't see random spleenic arteries and spleenic veins jumping in over here so that's why it's called the hilum the main function of the spleen is that it's going to be filtering your blood that's what it does inside the spleen there's two different types of tissue you have the white pulp and the red pulp it's called White pulp because it literally kind of looks white underneath a microscope the what the white pulp is is it is lymphatic tissue particularly lymphocytes um and macr fases and so these are going to be searching for substances within your blood as it filters it of items that you need to get rid of so destroy foreign materials and bacteria the other type of tissue that's found in the spleen is the red pulp red pulp does three main functions number one it's going to get rid of anything that's dead decrepit or decaying inside your blood so macroasia blood cells platelets it's going to help get rid of and process second thing is it stores up to a third of your platelets platelets are not produced in the spleen they are produced by humo poesis in your red bone marrow but they are stored here and then when you are a fetus most of your blood cells are actually produced here in the red blood um in red pulp during your fetal life and so that's kind of why this is red in color versus white in color because a lot of what the red pulp does deals with your blood you are probably familiar that you can live without your spleen so splenectomy is the removal of a spleen often times a splenectomy is due to the fact that somebody had a posterior abdominal injury causing the spleen to basically erupt sometimes there can be a strong infection that will attack the spleen a tumor cancer can cause the spleen to need to be removed because of the spleen function to filter your blood and cancer cells can travel in the blood it can also have to be removed for example during CLE cell anemia because in CLE cell anemia the cells have a hard time traveling through the blood vessels which can cause the spleen to basically get swollen blocked up if you get your spleen removed you can of course survive but you will be somewhat immunosuppressed because of the actions that your spleen does when it's inside your body so therefore you might be more at risk for getting a an infection that could kill you because you were missing the ability to filter out those items and destroy it only from your spleen organ you have other structures in your body that can help destroy things but your spleen can't contribute to that so the final tissue that's part of the secondary lymphatic organs are lymphatic nodules lymphatic nodules are different than lymph nodes because lymphatic nodules don't have a capsule lymph nodes do so instead lymphatic nodules kind of take up a ununiform shape to them whereas your lymphatic nodes are just tiny little beans circular in shape lymphatic nodules are not that we find lymphatic nodules scattered throughout your body in places that are right near a mucus membrane and you can see examples here along your gastrointestinal tract urinary system reproductive tracts respiratory Airways essentially lymphatic nodules are found in places that are open to the outside so your GI tract along your mouth your anus urinary system right around your um Ure reun your bladder reproductive tracks so in the the the vaginal Canal uh uterus to be able to help again with openings respiratory Airways so right along the pathway of your tricka and your mouth down into your lungs the reason is is that you can have substances come in on whatever you are eating via the gastrointestinal tract or coming in the air that you breathe in it can also come from substances working their way back up the urinary system like in UTI reproductive system having the bacteria work through a female vaginal Canal so lymphatic nodules are scattered around places usually that are open to the outside often times lymphatic nodules in these areas are also called maltt tissue maltt stands for mucosal Associated lymphatic tissue so that's what it means we're going to take a look here at the tonsils so tonsils are a perfect example of lymphatic nodules CU tonsils are going to be surrounding your mouth and your nasal cavity which is where food and air and fluids are going to pass through so that forms a beautiful ring right around your oral cavity and your nasal cavity there are a total of five lymphatic tonsil nodules so out of the five there is only going to be one Fang tonsil the Fingal tonsil is found in the FX and it is a single adenoid this can be removed when some someone has a tonsil activity to remove tonsils but sometimes it is also removed in individuals who have a tough time breathing and are snoring because it's up in the the nasal cavity and then can be removed to help aid with lessening of the snoring as well as breathing the palentine tonsils there are two of them one on either side so here's a picture of swollen palentine tonsils and you can see that in this situation when someone gets tonsilitis or inflammation of the tonsils due to strip bacteria for example they can swell so much to the point that it nearly closes off the opening of the fucis which is from your mouth into your esophagus so those are the two tonsils in the pallet which is why we call them Palatine and then on the back of the tongue is where we find the lingual tonsils there are two of them lingual means tongue and so we see them on the very posterior surface you cannot see them unless you got your tongue removed or were able like smashed on your tongue to see the far back so you can't pull out your tongue far enough to see them but they are on the back side so again all five of them help protect the air that comes into your nasal cavity and oral cavity to filter it food that comes in and um any fluids as well and they can become again inflamed or get larger when there is a reaction to anything foreign that comes inside the body so along the lines of tonsils when someone has tonsilitis this is inflammation of the tonsils so acute tonsilitis just means an infection the most common effected tonsils are the palentine because the palatines are right around that fosis or that oral cavity and again they can get so large that they might obstruct the person's ability to swallow classic signs of tonsilitis uh fevers a sore throat difficulty swallowing tonsilitis can be caused by both viruses and bacteria bacteria is probably one you're most familiar with strep throat if a person gets tonsilitis again and again and again frequently in a short amount of time this is considered to be called chronic tonsilitis and sometimes that warrants a removal of them called tonsilectomy in tonsilectomy the general removal will be of the palentine so the two palentine and then commonly they also then will remove the Fang geot tonsil not all ear nose and throat doctors will remove the noids or your Fingal ones they might just move the palentine they can also remove the lingual tonsils but that's not typically the common protocol for treating and getting rid of the tonsils and a tonsilectomy