Immune System

okay how are we doing everybody welcome to week 12 this is the last week of the trimester which is really exciting I was so excited that my hair went white so I apologize for that this week we're doing the immune system now before we begin I need a couple of thumbs up on the chat maybe people saying sounds good looks good here is everything okay in regards to the quality of this live stream video how's the quality can you hear me or good is the sound quality okay is the visual Cauley okay you can get it all going or good or good okay wonderful thank you alright so immune system week 12 last topic my aim for this week is to make it as easy for you as possible we need to go through a number of different points now if you've watched the lecture I think the lecture really covered everything in a really nice way so what I want to try and do is bring everything together concept wise for you so the lecture spoke about it in parts segregated it out I'm going to reiterate the important points for you and I'm going to try and build a bigger picture so I think the best place to begin with for this is to start with the flow chart of the immune system talk about what the immune system is and then we can talk about the various components of the immune system so when we begin the immune system is a way for our body to protect ourselves defend ourselves from invading pathogens and also to create a memory in case we get attacked again from these invading pathogens so the immune system is a great way for us to basically respond to anything that shouldn't be there and to create a memory against it so when we look at the immune system you can divide it into two major sub categories you've got something called the innate immune system and you've got something called the adaptive so these are the first two subdivisions now if you have any questions at all just pop it through the innate immune system is what it sounds like this immune system is this division of the immune system is nonspecific so it doesn't really care what sort of pathogen is attacking you it could be a bacteria it could be a virus it could be a fungi for example all right so at night let's write some important points is nonspecific the other thing about the innate immune system is it does not develop a memory now what I say memory what we're talking about here is the type of memory you develop once you get infected by a particular pathogen and that pathogen tries to infect you again you fight it off quickly so often things like hepatitis for example some types of influenza you can get infected you get sick you develop antibodies which is the memory part of this adaptive phase and then if you get infected by the exact same pathogen again you don't get sick because you've developed your immune response to be able to attack it and kill it off before it does any harm to you so the innate division of the immune system has no memory doesn't do that okay so it's nonspecific it has no memory and it's the first defense first line of defense all right so these are the three first important points for the innate immune system now when we look at the innate immune system there's a couple of subdivisions we need to look at first of which is skin and mucus basically when we talk about being invaded by viruses bacteria fungi they're usually coming from or all the time they're coming from outside of the body if they're coming from outside of the body they're trying to get into the body and a lot of the time if it's a virus it wants to hijack our cell our DNA to make more copies of itself if it's a bacteria it wants to use our environment to make more copies of itself and the same goes with the fungi as well so we need to try and stop it from getting in and so our first line of defense our first barrier is our skin and our mucous lining so for example you know already that your skin is made up of stratified squamous epithelia now squamous means squished stratified means many layers you did this in your assignment right so stratified squamous epithelia this skin barrier is so important because when this let's just say bacteria for example tries to invade you it's going to come into contact with many layers like a brick wall that's going to be hard to penetrate in a difference in it in addition to this I should say let me get another pen in addition to this so stratified squamous epithelia right in addition to that we have particularly glands that secrete substances like sebum now sebum comes from sebaceous glands and it's like an oil substance and this oil substance actually contains enzymes that kill off bacteria so you're right sebaceous fluid we also have enzymes so let's write that down enzymes on our skin and in our mucus and these enzymes include things like defenses which sounds like exactly what it does it defends us they break down bacterial walls now if we look at mucus so we have a question is this like the cilia within the respiratory tract good question Jade so if some of you did the respiratory tract for your assignment you would have found that in the respiratory tract it's not stratified squamous but it's pseudostratified columnar epithelia that's because columnar cells secrete mucus most of the time and the mucus it secretes is sticky that's why we're looking at so let's just say this pathogen so remember a probably should define the stone a pathogen is basically a foreign substance that's trying to invade your body that's a pathogen so a virus bacteria fungi they can be pathogens right so let's just say pathogens not getting through the skin but you inhale it either through nose or through your mouth or you swallow it luckily for us the inside of our hollow cavities is also lined with epithelia and a lot of this epithelial releases mucous like in the respiratory tract now what mucous does is it captures or traps these pathogens traps pathogens and that's the mucus and if we're talking respiratory tract the cilia which are the little hairlike things that are on the ends of the pseudostratified columnar epithelia it pushes the mucus up push it up up up so goes up up up up up the trachea into our Farington we swallow it into the stomach now why into the stomach now sometimes we cough it out but if we swallow into the stomach the stomach has a pH the stomach has a pH of between one two three and what this will do is will denature which means a breaks down this pathogen so it doesn't harm us so as you can see skin and mucus being our first line of defense is a really good way of stopping anything as the first port O'Call okay now in addition to skin and mucus because sometimes what can happen is these pathogens can move past their skin maybe through breaks in our skin for example I can move past the mucus and it can get into the cells of our body or between the cells of our body or within the blood of our body now if this happens we still have this innate nonspecific response before we move to this adaptive spots so let's have a look at what this response now is this is now internal defenses still nonspecific now there's different types of internal defenses that we have so for example we have cells certain types of cells that can help protect us we have chemicals and we have physiological response again none of these are adaptive none of these are acting as though they know what this pathogen is they don't know whether it's a virus or a bacteria they are just doing what they do all the time if any pathogen comes in let's first look at what the cellular response is inside the body that's nonspecific so the first type of cellular response we get a phagocytes phagocytes now one type of phagocyte is that of the macrophage you can see that phage or Farge which sits at the beginning of phagocytes and at the end of macrophage means that eight phage means to eat so a phagocytic is just a cell that eats and a macrophage is a large cell that eats and basically what these cells do is they ingest pathogens so if it's a bacteria for example let's just say I've got a bacteria here we bacteria that's invaded our body now what we know is that bacterias and viruses they have proteins and remember last week when I spoke to you I spoke to you about blood typing and I told you that your red blood cells or erythrocytes have flags called antigens on them and what these flags do is tell you whether you're a B or a B or oh similar right bacteria have flags to say what it is now the great thing is our body can recognize whether these flags or protein antigens belong to us or a foreign and that's perfect because when we can recognize this we can call in the adaptive system and they can fight it off and they can create immunological memory to the flags that's actually how we create antibodies and sometimes lifelong memory against particular diseases is because we recognize those flags so if a bacteria comes into the body macrophages like phagocytes for example phagocytes like macrophages what they'll do is they'll come in and they'll engulf they'll engulf that particular bacteria for example and what will end up happening is this macrophage will present some of the flags on its surface and this is important because when the macrophage has some of those flags on its surface it can then call in the adaptive immune system T cells B cells and then create an immunological memory so it's now what we call if it takes those antigens and presents it the macrophage becomes an antigen presenting cell really important and it's these antigen presenting cells that can get the T cells and the B cells to produce some sort of memory okay so that's super important so again if there's any questions you just let me know the next type of cell that you need to know are the NK cells known as natural killer cells so they've got a great name natural killer cells NK now what natural killer cells do is it pretty much what that sounds like it just kills that pathogen but it does it through a process known as apoptosis apoptosis if you watch the lecture I would have told you I think I would have told you that apoptosis is a latin term or maybe greek term for when the leaves fall off the trees in autumn beautiful name basically it's a programmed cell death because when the leaves fall off the trees in autumn it's programmed it happens every season and it looks like the trees are dying apoptosis is programming a cell to die and that's what NK cells do they find the pathogen which may be a bacteria for example and they program it to undergo apoptosis now apoptosis is a very specific type of cell death it's different to necrosis so you always think necrosis cell death apoptosis cell death what's the difference the mechanisms by which they die are very different in apoptosis what you find is the cell all the intracellular compartments and organelles and so forth they slowly degrade so the cell wall remains intact but all the intracellular components degrade until they're basically nothing now this is important because in other types of death like necrosis the cell can swell and burst and release its products in necrosis and if it release its products this can lead to further inflammatory or immune based issues right so it can cause disease so in apoptosis we kill it from the inside and that's what these NK cells do any questions nope cool all right so they're the two cells that I need you to know when we look at chemicals again nonspecific chemical responses can include what's called the complement system also known as complement proteins now there's around about 30 of these complement proteins they're all I think most of them at least are produced in the liver if you ever get asked the question about a specific protein and the question I ever asked you where's it produced and you don't know guess the liver most of them are alright so complement proteins what they do is this there's many different types I don't need you to know the complement pathways there's three major compliment pathways right there's a classical pathway an alternate pathway and a lectin pathway and all three converge I don't need you to know them what an idiot knows what happens when they converge is basically compliment proteins it's in the name they complement all the other immune responses they support them they call upon them so complement proteins promote what I'm going to talk about here which is inflammation they promote fever they promote these cells phagocytes macrophages natural killer cells they promote all these processes that's what these complement proteins do now there's other proteins within the body which are similar to complement proteins that also promote or support immune function and these are called cytokines and there's a couple of different types of cytokines like interferon into the Lucan tumor necrosis factor these are all cytokines and what these cytokines do is very similar to complement proteins they boost I shouldn't say the word boost I don't like using the term boost the immune system what they do is they support the immune system now while the complement proteins really like to focus on these sort of nonspecific promotion of the immune system many of the saticons while they do do this they also promote a lot of the adaptive immune functions and they promote things like T and B cells coming along to help a glutton eight surround and destroy some of these pathogens so these are chemicals proteins predominantly within the body nonspecific that's the more this function in apoptosis what happens to the cell once it dies ah that's great question once it dies all the components get recycled so some will just degrade until it's nothing and things like Liza's ohms and peroxisomes will come along and they'll destroy it until it's basically non-existent but a lot of the time a lot of the components because cells or cells or cells are either made up of fatty acids and made up of proteins they're made up in nucleic acids we take them and we recycle them we rather get rid of them urination defecation or we recycle them so hopefully that helps Cindy now let's look at the physiological response the physiological response are two things it's inflammation and fever which are two important concepts especially leading especially as a nurse or an inflammation we've all experienced inflammation and we've all likely experienced fever and it might be worth us having a bit of a chat today about what's happening with the covert 19:00 situation in regards to some of the immune responses just to help you out so first let's look at inflammation inflammation is part of the innate immune system it's nonspecific so inflammation occurs anytime there's damage to vascularized tissue all right so if there is tissue of the body that has no blood supply and it's damaged you're probably not going to get inflammation now you're probably thinking well what tissue doesn't have blood vessels or as vascularized and a lot of cartilage damage to cartilage is very hard to fix because the inflammatory process often doesn't occur there now that's not necessarily true but because there's vascularized tissue in the periphery of it and it can lead to tissues having these chemicals and substances from the inflammatory process sort of diffuse through to the cartilage but a lot of the time doesn't necessarily happen in cartilage all right this is what happens in inflammation this is what you need to know this is what you need to know for the future is it common to have inflammation after surgery a good question Sabella inflammation weapon anytime there's damage to vascularized tissue so for example if you go in for surgery and they've had to cut through right some portion of your skin or body that's damage to vascularized tissue so inflammation is a normal response to occur what they usually do is they give you anti-inflammatory drugs and I'll talk about those in a second and what they should do is at least in part quash some of the cardinal signs of inflammation all right let's write these down there's four cardinal signs of inflammation for signs of inflammation that you've all seen you've all experienced right these are the four cardinal signs for signs of inflammation these are redness pain heat and swelling all right so we used to I still have to remember the Latin names of these I don't know if what redness is rouble pain is dollar heat is quell or and swelling is tumor oh that's right because tumor is simply the Latin term or Greek term for swelling so they're the reason why they've got all these old Latin terms ruble dollar Cal or tumor is because these four signs of inflammation have been recognized for thousands of years the Greeks recognize these basic four signs of inflammation and they always happen when you have an inflammatory process is loss of function another Jay brilliant yes lots of function is a more recent addition it's it's the fifth sign and I don't know what the Latin term it's something like funk functional I don't know I'm making something up if I say something there I remember reading something in a textbook yeah Jade 100% lots of function is the fifth sign all right so let's talk about how these four or five signs come about through inflammation so this is what happens if you have a blood vessel specifically a capillary bed you know that basically when your heart pumps right your heart contracts pushes blood out of the aorta the aorta is a large artery now in the aorta you're going to have blood which contains oxygen and nutrients right it's pumping that blood through arteries and our dues get smaller they're a branch more but they get smaller as they get smaller they turn into arterioles as those Arturo's get smaller they branch more and they turn into capillaries now capillaries have holes in them and this is a capillary bed right these capillary beds have holes in them and the holes are there because it's at the capillaries so arteries fluid doesn't come out gases don't come out nutrients don't come out and arterioles nothing comes out but at capillaries the blood that moves through begins to leak out now what specifically leaks out our capillaries are things like oxygen and nutrients oxygen and nutrients the reason why is because it's a capillary beds where we have cells that we want to feed these are the tissues of our body right so we want to give it oxygen nutrients now as the blood continues through it turns into the venous system right venules veins and then that goes back to the heart and as it goes back to harlot's low on oxygen lower nutrients so it needs to get oxygen it needs to get nutrients and so forth all right so we're at the capillary bed we haven't spoke about inflammation we need to start doing it it's damage to vascularized tissue this is tissue here's the blood vessel so this is vascularized tissue let's just say something happens you cut yourself you damage that tissue so you step on a needle you step on a nail you step on something right something that cuts your skin you've damaged these cells when you damage these cells they start to release important chemicals now there's a lot of cells present under your skin and your new skin called mast cells so just saying this is a mast cell this is probably another cell that you could add to this nonspecific list let's add it mast cell right and what happens when you damage these cells and these marcelles is they start to release chemicals yeah it's a whole bunch of these chemicals but there's two you need to know histamine and prostaglandins here's the main and prostaglandins what histamine and prostaglandins do is something really important histamine and prostaglandins they tell the blood vessel to dilate histamine and prostaglandins tell the blood vessel to dilate now think about this if this blood vessel dilates if this blood vessel dilates what does that mean anyone have any idea if you dilate a blood vessel remember Bloods coming in what does that mean if it's dilated what do you think's going to be their response what do you think is gonna happen any ideas its dilated swelling so swelling in what way before swelling if you dial out a blood vessel there's more or less blood coming what do you think increased movement of o2 and nutrients yeah yeah increased fluid yes exactly it's exactly what's gone up and you histamine and prostaglandins dilate the blood vessel so more blood goes to that area more blood moves to that area that's the first thing that histamine and prostaglandins do second thing histamine and prostaglandins do is they widen these holes in the capillary beds they widen those holes in the capillary beds now usually like I said to you before it's just oxygen and nutrients that leave the holes in the capillary beds are too small for proteins and cells to leave now what are the cells red blood cells white blood cells right but now histamine of prostaglandins have widened the gaps in the capillary beds so now everything leaks out so it's not just oxygen and nutrients that are leaking out its cells and proteins including immune cells so the reason why this is important is because the immune cells that are leaking out are going to identify if you've damaged this tissue and there's any bacteria that are present the phagocytes that are present are going to gobble it up and ingest it and present the antigen all right there's going to be Team B cells floating through they're gonna play their role now remember this right I told you last week I introduced it to you last week but I'm going to talk about it again your leukocytes which are your white blood cells as I've types and I told you to remember them by saying never let monkeys eat bananas right these are the five types of white blood cells neutrophils lymphocytes monocytes eosinophils and basophils great thing is I don't expect you to know anything about the last two this trimester but we're going to talk about the first three all right what happens is when you have inflammation the first leukocytes that come through are the neutrophils and monocytes the very first one are the neutrophils number one they're the first that come in with inflammation and what neutrophils do is they basically played this similar role as these macrophages they start to gobble up any pathogens that are present my other sites are the second to come through they come in a day or two later so now you got monocytes and this is thing monocytes have big intravascular intracellular nuclei and what happens is when the monocyte comes through and comes out as soon as the monocyte leaves the blood vessel it turns into a macrophage right so it starts to gobble things up to over a couple of days the neutrophils and the monocytes or now macrophages begin to die they've got up all the pathogens they brought them in they've inactivated them so they don't make you sick and what now starts to accumulate at the site of damage is puss-puss are dead white blood cells specifically pass is dead neutrophils and dead monocytes okay that's what's happening here for pus lymphocytes which we're going to talk about soon it's part of this adaptive system lymphocytes are T and B cells I'm going to talk about that process shortly but firstly I want to talk about what happens when these macrophages present with the antigen right because think about it oh no before I do that talking about how we get these particular things right alright let's start with redness when you get inflammation the site becomes red why because more blood has moved to that area those blood vessels dilate so there's more blood in that area redness you get pain because the fluid that leaks out puts pressure on nerves that are present right and these nodes of pain receptors so you get pain in addition to that prostaglandins stimulates it's like a neurotransmitter it's a chemical that stimulates pain receptors too so there's double tick for pain the pressure is causing nociceptive pain and the prostaglandins are stimulating it causing another nociceptors type of chemical poem hate it becomes hot in that area because more blood is getting to that area blood is 38° like we said last week so it gets hot swelling occurs because fluid has leaked out and it's now sitting between the tissues so the site begins to swell tick and you get a loss of function and the loss of function is because of the swelling so when that area becomes swollen you begin to lose function does that make sense to everybody while we get those four to five cardinal signs of inflammation because histamine and prostaglandins as the two main chemicals dilate blood vessels and make it more permeable increases vascular permeability that's what it does alright so hopefully that makes sense right now what I want to talk about is when we have all this foot so when you think about it blood vessel let's talk about there's no inflammation right because it's important there's no inflammation and we want to feed these tissues out here all right no inflammation as the blood comes past plasma leaks out and oxygen and nutrients leaks out great but there's also fluid right the fluid got leaves the blood the cells like the red blood cells and the proteins they all remain inside because they're too big to leave but oxygen nutrients and fluid leaks out now we have as am i Oh five to six liters of blood in my body five to six litres of fluid a good percentage of this fluid is leaving now now we need to reclaim that I need to keep that five to six liters of fluid in my blood so we need to pull it back in the great thing is because there's proteins and cells inside the fluid there's an osmotic gradient osmotic pressure water gets pulled towards or fluid gets pulled towards areas of high concentrations of stuff so the great thing about keeping proteins and cells in the blood is it pulls the fluid back in and it reclaims the blood fluid that's what the proteins and cells do perfect but when you have hopefully that makes sense if that doesn't make sense you let me know please but when we have inflammation and D and the blood vessel becomes much more permeable what ends up happening is the red blood cells and the white blood cells and the proteins they're all now out here right so how do we reclaim this fluid that's why the fluid comes out in swells but we need to reclaim the fluid yeah the camera is out of focus make sure you just click out click back in because I think it should be okay ISM is everything okay for most people just let me know or good now okay great all right so if we've got these big gaps and the fluids leaking out we need to find a way of pulling it back in all right we can't pull it back into the blood vessel straight away because we don't have the proteins we don't have the osmotic gradient to pull it in so what happens is this all the fluid that's floating between the cells called the interstitial gets reclaimed by a lymphatic system our length now tell me if you can't see the color green weird these blind ended vessel vessels called lymphatic vessels and what they do is they reclaim the fluid now again we're not let's let's just say we're not talking inflammation and we're saying that not all the fluids being reclaimed right into the lymph live Chuck's it back into bond goes to the subclavian vein throws it back into the blood right now there is inflammation heaps of fluid this floor jumps into the lymphatic vessels all right this can be happening anywhere right anywhere that inflammation is occur but remember I said we're going to have those neutrophils and those monocytes basically macrophage acidic cells that are here and they've got up some bacteria and they're presenting some of those antigens on their surface so I've got a macrophage here and it's presenting some bacterial antigens on its surface it jumps into the lymphatic vessel and gets carried with the lymph which is the lymphatic fluid now we're gonna this is now my segue to talk about lymph from them Phatak fluid before we move on to the adaptive system because it's entwined in the leaf in the lymphatic fluid right in a lymphatic system we've got all these vessels we know we go arteries and veins but we've also got lymphatic vessels now these lymphatic vessels reclaim that lost fluid but lymphatic vessels and the lymph system play three roles that I want to talk about right so length or the lymphatic system play three roles right the first one is what we've just stated it reclaims lost fluid the second role it plays is it's actually the main site where fat gets absorbed so usually glucose gets absorbed into the bloodstream right so that's part of carbohydrates amino acids absorbed into the bloodstream but fatty acids well they get absorbed into the lymph so it's a second function third function which is going to be its role today is an immune function now what we're just spoken about is that we've got macrophages in this fluid that it's just require but it's gonna play roll with this immune function which we need to talk about what if you had vasculitis as there is inflammation of blood vessels is it because macrophages I guess that's not working yeah so you can have inflammation of any tissue including the blood vessels themselves because they're made up of epithelial cells could endothelium and they can become inflamed it just means that what happens is that the blood vessel itself gets inflamed but you still get the same signs of inflammation or at the redness pain heat swelling and so forth all right so what happens is that lymph fluid can gather and it gets and it drains into particular is there before it drains it to the bloodstream it goes through what we call lymph nodes or lymphatic tissue all right lymphatic tissue lymph is there it's got the name live because it has as lymphocytes so lymph because it houses lymphocytes now it's not the site of lymphocyte production it just houses lymphocytes now lymphocytes like I said to you earlier are team B cells right so lymphatic structures house T and B cells now you've got primary and secondary lymphatic structures primary lymphatic structures T stands for thymus B stands for bone marrow these are primary lymphatic structures these are the sites of so far this is the site of T cell maturation bone marrow is the site of B cell maturation in actual fact bone marrow is a start of T and B cell production but bone marrow is B so naturally T T cell maturation then from there Team B cells have a population within secondary structures so they don't mature in these secondary structures it's the farmers and bone marrow where they mature question might be where's the thymus so you I would hugging your trachea your thymus is below that just above the heart at the sternal region okay the mediastinal just up here all right now secondary structures include things like lymph nodes tonsils peyer's patches appendix these are some secondary lymphatic structures now tonsils and PI's two patches are often termed a molt and molt there is four mucosal associated lymphoid tissue mucosal associated lymphoid tissue M alt and basically it's the tonsil but any place that's got mucous mucosa right epithelium that secretes mucus that's your intestines that's the back your throat so you got your tonsils at the back of your throat you know there's different types of tonsils that we have and you got peyer's patches there in your intestines small intestines the appendix the beginning of the large intestines right I'll rather down PI's patches is small intestines appendix is the start of the large intestines but again their role right is that they house and that includes the lymph nodes they house T and B cells which means they play a role in responding to pathogens that are being presented by macrophages so if you've got some sort of bacteria or virus floating through your body that's not in these original areas between tissues and they've been reclaimed by lymph they've been pulled from the blood into the lymph so if it's in the blood it'll ultimately get into the lymph when it's in the lymph depending on where it is it goes through these things if it's at the back of the throat tonsils if it's in the neck region or the armpit region of the inguinal region lymph nodes so lymph nodes are in various regions right you've got cervical lymph nodes which is in the neck right remember when you get sick you ever saw right you can you say all my glands are swollen you're just feeling your lymph nodes they're not glands right survival axillary which is under the arms and inguinal they're the major regions of lymph nodes okay and like I said tonsils back of the throat peyer's patches small intestines appendix large intestines ah Thank You Jay spleen it's not about the spleen so the spleen is a very important secondary structure too it's very important Thank You Jade totally forgot so what the spleen does while these will respond to bacteria that's jumped through blood strew the blood and the lymphatic system the spleen is going to be directly associated with the blood so there's a bacterial infection in the blood that's going to be going through the spleen now the thing that they all have in common is they all have a lot of connective tissue and we know connective tissue is cells gels of fibers the cells are going to be immune cells predominately the gels don't worry about it's just fluid basically don't stress but the fibers are important here and there reticular fibers so they're fine fibers they form a meshwork and it's this mesh work like cotton wool that traps particles moving through that's what's so important when the this lymph fluid moves through with any invading pathogens or macrophages that are holding the antigens they get caught up in this connective tissue in these particular areas and then they get activated by stimulating team b-cells and that's what I'm gonna talk about now I'm gonna use the example of lymph nodes to highlight how this whole process occurs if there's any questions let me know let's have a quick drink I thought the appendix is a vestigial structure people say that but it's not vestigial is a term that's used as a an evolutionary leftover but it's not the appendix plays a big role plays a big immune role and the appendix plays a role if you tend to have some issue like riah due to infection and you end up releasing a whole bunch of your gut flora through diarrhea right you need to repopulate your gut flora and that's what the appendix does the appendix has this huge amounts of gut flora and bacteria and so that's so high post oral and immune Earl and it also plays a repopulation of gut flora role you can live without it so there they're necessary but they're not required if that makes sense what happens when you get appendix and tonsils removed does that affect immune function to a small degree yeah it can so it can increase the likelihood of infection occurring so increases the amount of so here's the thing everything's a fine balance right so if you have bacterial infections and it gets caught in the tonsils and it's destroying them breaking them down but it's not cleared away then that can get inflamed because that can cause damage to the cells and damage to cells that have blood vessels cause inflammation and inflammation over a long period of time is not good so again it's a fine balance so tonsils are great but if they constantly get inflamed because they're not being cleared then they can be detrimental removing them stops that and what the plan would be is that again it's it's a line of defense there's other lines of defense so it's not going to be something like a make or break for you getting extremely sick because there's going to be other mechanisms swung it into your stomach first line of defense other sorts of lymphoid tissue right which could include the moult's and so forth so it's not a big big deal you can easily live without those okay and the threat of constant reinfection of those tissues especially the appendix it's the risk is too high if you have appendicitis got to take it out because if the appendix can burst right if it becomes too inflamed it can burst and it bursts into the peritoneum which should be should be an environment that's clear of any bacteria all right but it explodes all that bacteria that's present in the appendix and causes infection and inflammation in the peritoneum and that's very bad an infection the peritoneum not good not good at all alright so let's talk about what happens at the lymph nodes so lymph nodes are these bean shaped structures they've got the lymph fluid coming in and through various vessels right and they get a little capsule so they've got this outer capsule that you can see here right now this outer capsule is where the lymph fluid originally starts to move around and shift through but what you find is that there's these individual little nodule like areas now it's these areas that are important because the lymph node is made up of that reticular tissue the fluid that's floating through this capsule area leaks into these areas and these areas has three different types of cells you need to know all right on the outside its housing b-cells so these are b-cells now what did I say about B cells B cells are produced in the bone marrow they mature in the bone marrow but I haven't told you what they do yet here they're both part of the adaptive immune system which were yet to discuss but we're starting to discuss it here and then in the middle what we have are macrophages and dendritic cells okay let's label them macrophage and dendritic cell okay this is what happens so as this fluid floats through let's say it's happening from an inflamed area right tissue that has inflammation looks like I froze for a little bit hopefully I'm all good can everyone still see me just let me know if you can hear me and see me okay sorry all right so what we've got is we've got all this fluid that's coming through from an area of inflammation this area may contain bacteria still right this fluid may contain bacteria or it may contain fix out perfect or it may contain some of those macrophages right neutrophils monocytes that are presenting the antigen these bacteria will have the antigen so maybe the bit of the bacteria didn't maybe not all of that bacteria got destroyed at the site of inflammation but some did so got both bacteria and the macrophages coming in with those antigens now as they come in this is what happens the macrophage is present inside the lymph nodes attack and destroy just like this one did so now we've got an accumulation of all these macrophages and they're holding on the engulf that bacteria or virus they've engulfed it and they've popped off that flag that antigen and they're waving it so we're waving with those antigens here in the middle why why do we have this what's the point of waving these antigens okay when we have like I said earlier when we are the macrophage that's holding that antigen what this does is that antigen is a flag to call in T cells so the T cells see that antigen that flag and what the T cells do is a couple things one it creates a memory to is it calls B cells and what now happens is it cause B cells in and the B cells witness that ain't an antigen and they do something special B cells turn into something called plasma cells and plasma cells create antibodies so antibodies as many different types i ji ji ji ji a write antibodies now what antibodies do one of my quiz questions was what is an innate barrier I pick skin and I got it wrong well send me an email and I'll have a look for you because skin is definitely an innate barrier all right so let me just reiterate this point and this is what you need to know about team b-cells okay it's not just happening at lymph nodes it's happening at other lymphatic tissues all right so a bacteria has come in it's got its proteins antigens or a macro file just come in that's already engulfed a bacteria presenting an antigen regardless the macrophage is here in the lymph nodes will end up engulfing the pathogen and waving the antigen flag this calls in the T cells and remember the T cells are here so it calls in the T cells and the T cells recognize it they start to create a memory so these T cells end up these populations get bigger and bigger and bigger the cells grow grow grow grow grow because it's making more t-cells right the t-cells call in the B cells and the B cells now recognize this and they make a memory which means in addition to that the B cell population grow and divide grow and divide grow and divide bigger bigger bigger bigger bigger bigger bigger B cells when they want to create antibodies they don't create them directly B cells turn into plasma cells and plasma cells create antibodies does the macrophage signal T helper cells or just all T cells T helper cells at the moment it's - it's it's a lot of information to go through the T helper cells the cytotoxic T cells and all the various C b-cells this is what I want you to remember this is most important concept when it comes to team b-cells this is what I want you to know so B cells make antibodies but they don't make them directly B cells must turn into plasma cells and it's the plasma cells that make antibodies and it's the antibodies that have memory so T cells can have memory which means now this is what all this means the reason why all this happens is so that there is a memory of this nasty bacteria because if we get reinfected we don't want to have to go through the whole process of getting sick and trying to fight it off having inflammation having a fever which i've been spoken about yet but I will having inflammation having fever going through all this what it means is as soon as that bacteria gets into our body the T cells that now other memory will bind to it and the antibodies that have a memory will bind to it and they'll destroy it straight away that's exactly how this works all right antibodies with their memory what this is called is antibody mediated immunity antibody mediated immunity and there's different types now you can have antibody mediated immunity the last four years you can actually have antibody mediated immunity that lasts your whole life or you can have antibody mediated immunity that only lasts a couple weeks or a couple of months or maybe a handful of years sometimes we just don't know sometimes this is the issue that's happening with Coburn 19 so with covert 19 it's a virus right now viruses have antigens and when it infects the cells of our respiratory tract our macrophages engulf it digest it wave the flag this whole process happens we have an immunological response and we have antibodies that are developed memory so somebody who's a covert 19 you can take their blood and look at the antibodies floating through if they've got antibodies specific to covert 19 antigens it might indicate they have an immunity but it's not 100% and the reason why is the same reason why we can get a cold and then the next year get another cold I can check your blood if you've had a cold and you'll have antibodies for that particular cold but the thing is some viruses mutate really quickly which means that antigens change and if the antigens change these antibodies don't work very well then this may happen with Cova 19 we're not sure we need to know whether the antibodies that we get after being infected remain in the body for years or maybe just four weeks we don't know yes exactly Jade is because of mutation so mutation is simply a way of the virus of changing itself so that it can avoid these antibodies next time all right so let's now quickly talk about so I want to talk about antibody mediated immunity then we can finalize with fever and then after we do that I can talk a little bit about vaccines and we'll be done so any questions you just pop them through is everything making sense please say yes or no and if you say no ask me a question what's not making sense just pop it on the chat for me okay let's talk about antibody mediated immunity is the dendritic cell memory so oh yeah really good point in the in the lymph node those dendritic I didn't even talk about it excels Thank You Georgia okay in that lymph node the dendritic cells that are there right so I hope I said there's some dendritic cells what they do is remember I said that after all that happens the plasma cells that is those pay anybody's will get taken up by bender it excels now dendritic cells stay in the lymph node T and B cells they move out they move around right antibodies they move out and they move around then drin excels however they stay in the lymph node and I hold on to the antibodies they also hold on to antigens and they do this to constantly remind the T cells and the B cells of what had happened in the past it basically says remember we got invaded by that pathogen don't ever forget it so it's constantly priming T cells and B cells so if it does lose its memory the dendritic cells will stay there for decades holding on to the antigens and antibodies and basically saying do not forget so that's a good point Thank You Georgia and totally forgot about that all right next point is when we look at immune mediated sorry antibody mediated immunity there's different types so there's different ways of getting at it so what I just said was one way of getting antibody mediated immunity but there's different types do they die off then when they forget yeah so again it really depends on the antigen it depends on the type of pathogen that's invading us so mostly dendritic cells will stay there for many decades but it's going to be so everyone's different so it's really hard to make a blank blanket statement in regards to specific diseases and how long the dendritic cell stays with the memory of it and B and T cells for example right here are the two types you can have active and passive antibody mediated immunity ah basically it's how do you get antibodies to remember a pathogen all right active immunity is when it's active it's an active process which means your body's doing it so active antibody mediated immunity is when your body creates the antibodies itself you create the antibodies right passive immunity you do not create the anybody's you just receive the antibodies so creators that is what I should underline here you create the antibodies in passive immunity you receive the antibodies from somebody else right so it's a passive process alright there's two types of active and passive as well that you need to know so first time natural and artificial now if you watch the lecture I'm sure I'm sure of it that I would have just gone on I would have banged on about the natural fallacy it's so important especially as a clinician the natural fallacy is the fact that people hear the term natural and I think it's better they think it's safer they think it's normal and it's not necessarily the case natural does not mean better especially when it comes to biology especially when it comes to health natural just means there was no other engaging factor involved no other man-made engaging factor artificial just means that so natural versus artificial one is not better than the other right snake venom that's natural poison ivy that's natural aesthetic cyanide they're all natural okay doesn't mean those things are better and the same goes when it comes to compound that people ingest all right drugs people think I don't want to take a pharmaceutical drug it's not natural it's out of official so the rather take something like ginkgo biloba right well you're gonna remember that natural doesn't always mean better sometimes natural can be worse all right but I'm not gonna bang on that was in the lecture so what's the difference what is naturally acquired active immunity naturally quiet active in it so if active immunity is you currently anybodies yourself natural acquired means you basically got the infection and you crazy anybody's yourself so you created and I'm gonna just write this for antibodies you created antibodies after infection just like the process we just spoke about with the lymph nodes for example that's naturally acquired active immunity you created antibodies after infection artificial a quiet active immunity is again you created the antibodies because that's the definition of active you created the antibodies after not an infection from the environment that's what the naturals referring to you've got the flu for example so naturally quite as you got the flu you got the flu you got the viral pathogen you created antibodies against it that's naturally acquired active immunity artificially acquired active immunity these are received in an artificial environment meaning a vaccine so you created antibodies after vaccination which I would much rather prefer than creating antibodies after infection there are people out there that say they would rather get an infection and do it naturally than get the vaccination that's ridiculous it's ridiculous and it doesn't make any sense why would you want to get sick and actively put yourself in a worse situation when you can gather the exact same outcome and create the antibodies with that getting sick brilliant alright passive immunity passively quite immunity you receive there anybodys so you don't have an antigen that you make anybody's against you just get given the antibody now Watson at these two scenarios makes sense but what scenarios can you just receive antibodies from the environment breast milk breast milk is an example where this happens right mum's breast milk contains mums antibodies so basically she's just giving you antibodies in a natural environment and that's what's happening here artificially acquired passive immunity is when you get injected with antibodies and it's not that common but basically you get injected with serum injected with serum containing antibodies right and that can happen for some diseases so there are some diseases where we don't have vaccinations but what we have to give people serum for example alright so that is antibody media immunity let's finish let me talk about fever I'll write down the adaptive and then we're basically going to be done and that'll be our our sorted any other questions let me know alright lasting fever so what happens with fever is this again nonspecific cytokines play a role in fever and another chemical cord pyrogens pyro means via fever makes you feel like you're on fire so pyrogens we've got a question if there are antibodies in lymphocyte b cell plasma kill another person compatible blood plasma be given to a person as a transfusion for passive artificial immunity to help them find a pathogen good question so there was some talk about with the covert nineteen because we don't have a vaccine so there was some talk that maybe what we could do and it is feasible is to take individuals blood individuals who have been exposed to covenant and have developed antibodies take their blood pull out the antibodies spin them out so you don't have to take whole blood you take whole blood but you separate the anybody's out that way doesn't matter about the blood type and you can give those antibodies as serum as what I said was the artificially acquired passive immunity and that could provide immunity for a short period because over time those antibodies would disappear because they weren't made from you or by you so yeah really good question can can happen can occur it doesn't have to happen with compatible blood types because you separate out the antibodies from the blood now with fever what happens is you know about the hypothalamus right you know that when you got the brain at the bottom of the brain you get the hypothalamus with those two danglies called the pituitary gland all right now the hypothalamus is the master regulator it sets the body temperature of 37 degrees so if it's too cold it makes us shiver if it's too hot it makes us sweat right but there's a thermostat is set of 37 just like at home you set your air-conditioning unit to a particular temperature and as the environment changes that either blows out more cold air or blows out more heat right hypothalamus does the same so what happens is when you get an infection or a fever by pyrogens and cytokines come in and through a process that we don't know it changes the thermostat and pushes it up may push it up to something like 38 maybe 39 degrees so what happens now is that's the baseline and it thinks everything else is cold right usually 37 degrees the body's at 37 goes unperfect so you don't shiver or you don't feel too hot but what happens is it sets it to high so what happens is you get cold you think it's everything's too cold so you shiver and shiver and shiver even though it's not cold but that shivering produces more heat just so it brings the body temperature but by getting too hot you feel super hot and that's the fever now the reason why your body does this is because a lot of bacteria and viruses they can't survive at 38 and 39 degrees that's one thing they can't survive or that they don't divide they don't make more copies of themselves they just don't do it the other thing is the higher the body temperature the faster our enzymes work so the their immune system and enzymes work to destroy him break all these things down fevers a hard one because you get the question all the time is a fever a good thing or a bad thing depends depends on the situations like inflammation is it good or bad informations good short term bad long term fever if it lasts too long not good but fever in the short term is shown to be beneficial especially for viral diseases so it's really hard to say really hard to know whether a fever should be broken or not difficult um alright just finished with that adaptive immune system and will be done because and we've already spoken about it right I already said that the adaptive immune system made up of two things T lymphocytes and B lymphocytes also known as T cells and B cells cool and what the T cells they mature in the thymus and B cells when you tune the bone marrow that's why the B and T so don't forget that if you ever get asked a question where are they mature T finest B bone now not thyroid thyroid produced steroid hormone violence but like I said T cells can have memory B cells can have memory T cells call in B cells and B cells can produce plasma cells and plasma cells produce these antibodies I draw like a wide because that's this shape right we're done I think we've gone through all the really important points so hopefully that helps and this is your last tutorial for a mp4 trimester one I'll send you more information about the exam by the end of the week it's going to be online it's going to be multiple choice questions a hundred multiple choice questions in a hundred minutes but I'll give you more info it's gonna be value learning at Griffith page similar to how you do your online quizzes but I'll send all that email out right I've got to finalize some things first I've written the exam we're gonna finalize it is the quiz due this Friday next I've been very sneaky and I've made it June next Friday for you so I know that next week isn't part of the 12 weeks of the trimester but I thought I'd leave it open an extra week for everybody so the quiz is not due this Friday it's due next Friday thanks everyone

Channel: Dr Matt & Dr Mike

Views: 8,520

Rating: 4.9446368 out of 5

Keywords: immune, innate, adaptive, inflammation, antibody, immunity, leukocytes, white, blood, crlls, macrophage, cells, lecture, system, tutorial, university, nursing, medicine, lymph, t cell

Id: kD8YJvwp9-8

Length: 69min 25sec (4165 seconds)

Published: Sun May 31 2020