hi class Dr Jim here chapter 14 we are now getting into Immunology now I could spend days and days and days talking about Immunology but we're only going to cover it in these two in the next two chapters really the next three chapters we're going to look at the innate immune system in this chapter chapter 14 which is really what we consider non-specific immunity and so we'll talk about why that is non-specific then in chapter 15 we're going to talk about the adapted or sometimes a acquired immunity which you develop over your lifetime this is going to be specific and so this one targets very specific things so you need specificity you make memory and you do all these different things in in in the acquired immunity and so we'll talk about that in chapter 15 then chapter 16 is going to be looking at what the what happens when the immune system goes wrong and so we'll look at some of those different things where the immune system goes wrong where you have allergies sometimes you get tissue rejections sometimes you have antibody antigen interactions that are not good with the blood and other things like that and so we're going to look at all these different things in chapter 16 so today what we're going to be focusing in on is chapter 14 which is the innate immunity and innate immunity like I said before is non-specific that means you it doesn't matter if it's a bacteria a virus or a fungus it's going to attack it the same way every time okay and what we really concern ourselves with are really the first two lines defense with the innate immunity we look at mechanical barriers which is the first line and then the second line is your white blood cells now it's not all the white blood cells but really the ones that are responsible for phagocytosis inflammation and then also activating complement so we'll take a look at all these different things today uh that are associated with the innate immunity okay so let's get it let's get started with this uh process and look at chapter 14 so the first thing we're going to look at is what is immunology and like I said I could spend days and days and days talking very specifically about immunology and all the different parts people do specific research looking at immunology and spending a lot of time uh doing the research on that and so we'll talk briefly about what is Immunology in that we'll also look at the immune system again we'll talk briefly about what the immune system is and again it's your defense system against the foreign Invaders okay we'll talk about the three lines of Defense again the three lines of Defense in this case are going to be the first line which is your mechanical barriers your second line which is your white blood cells that kind of sit below the surface and then finally it's going to be your third line which is your acquired your BNT cells so and that will be chapter 15 and again how does each one act we'll look at what are the mechanical barriers that's the first level and then the second level is looking at phagocytosis and inflammation so what do those white blood cells do in that second line of defense that really add to your inate immunity okay so that's what we're looking at today all right so let's go on so what is the structure and function of the organs of defense and immunity so anytime we're talking about the defense properties of the human we're looking at Immunology okay and so that is the study of Immunology looking at the second and third lines of Defense specifically and again what does the immune system do the first thing that it does is it keeps a constant surveillance so think about this you have these cells going around your system that act like security guards and they're walking around kind of like a security guard would looking to check to make sure that everything is normal if things aren't right they respond and then they react and so that's what your immune system does once it recognizes foreign material it goes in and then it destroys it goes in and whmo it takes out the foreign material so we'll talk about what is foreign versus self and all these other things how does it recognize these things and so this is all a part of Immunology so one it's surveillance two is identifying and three is getting rid of okay and so so that's what we're going to be looking at today and again all these different systems interact with one another and we'll talk about these things as we go along throughout this throughout this chapter okay I wanted to start off with a few immune cell definitions and we're going to be talking about these things over and over again that's why I bring them up here one of the big things is the white blood cells the white blood cells are the wbcs and again these are the second uh types of cells that we have in our blood and so they they're outnumbered by far so so most of your cells in your blood are your red blood cells but the white blood cells make up about 1 to 2% of your blood and these are responsible for fighting infection and so these guys are there for surveillance destroying and acting upon foreign Invaders so we'll look at these things and the other name for them are called lucaites so we have we have the red blood cells which a lot of times are referred to as erthrocytes the white blood cells are referred to as the lucaites okay the lymph is the fluid that leaks out of our vessel so you might think that her system is a closed system and we talk about this in amp a lot that her blood system is a closed system that you have arteries leaving the heart with the blood it takes it back takes it in the capillaries the capillaries then go lead to the veins and then the veins lead back to the heart we call that a closed system or our vessels are very leaky and what that means is that fluid leaks out of our vessels all the time and there's a reason for this it's not that we're just made poorly it's because we want to make sure that fluid nutrients and cells get to those areas that aren't touched by the blood vessels themselves and so these are important so it is okay to have leaky vessels and we'll talk about that when the fluid does leave the leave the vessel we call this lymph and lymph is the extracellular fluid that eventually returns into circulation through the series of vessels called lymphatic vessels or lymphatic channels and we'll talk about that as well throughout this uh chapter another thing that you're really going to hear probably not so much in this lecture but in the next lecture is the difference between nonself and self nonself is anything that's foreign that's not supposed to be there self is anything that's supposed to be there now we have markers on all our cells except our red blood cells that tell us that this is us don't attack and so we'll look at that in chapter 15 and then again in chapter 16 when this doesn't work and so that's the difference between non-self and self so we're looking at all these different things today in that and kind of giving you an idea of what these things are all right so we're we're going to look at the host defenses and again we can break it down into two main systems the innate system which is your natural defenses these are what you're born with okay as soon as you come out of the womb of your mother you basically now have these innate uh defenses that can attack anything that comes into your body now these aren't the best defenses in the world but they do K keep you pretty healthy throughout your life okay and so these things are again are nonspecific and they'll attack viruses bacteria fungi parasites it's the same way that they would do any other organism that they find foreign the other system that you have is called the Adaptive system or the acquired system and this is what develops over your lifetime this develops when you get exposed to things when you get vaccinated you make memory to these things it's very specific it remembers specific things you come in contact with during your lifetime and then when you come to come in contact with it again you fight it and you beat it okay and so that's the idea so today we're going to primarily look at the first and second line of defense if you look down here again these are both innate these are both nonspecific and again no memory associated with this and these are the different things we're going to look at so it seems like there's a lot of things but we're going to talk about them pretty quickly the third line of defense is going to be chapter 15 so we'll wait and talk about that in chapter 15 but that's the acquired or specific immunity as we look at it all right and again we've already talked about this so I'll go through this real quickly but we have the first line these are your mechanical barriers these are anything that are found around the portals of Entry so remember we talked about in Chapter 13 how things can get in when things get in we need a way to stop them from getting in and causing attachment so if we can stop them when they come into us that is our first line of defense so think about any openings that you have we have lots of mechanical barriers that keep these things out the second line of defense sits underneath all the tissues and so it's kind of once that first line of defense has been penetrated the second thing that the microbes want to do is attach these guys are ready to attack when these guy when the microbes want to attach and so we're looking at now inside the tissues around surrounding the tissues in the um connective tissue the fluids things like this that's where the second line of offense is the third line of defense is going to be in the cells in the tissues and everywhere else but again this is going to be the very specific uh area and we're going to attack this head on with these specific cells the B&T cells with antibodies and t- cell receptors and again very specific specific and we'll look at that in chapter 15 all right let's move on so first talk about the first line of defense so this is keeping you healthy from the outside world so let's take a look at what is the first line of defense so the first line is really any mechanical barrier that we have around the portal of entry and again we've talked about the portal of entries these are things like your nose your mouth your eyes your ears you know your skin those are your portals of entry and so we have protective mechanisms around those areas is to keep the microbes at Bay or at least keep them from getting in any farther okay and so our skin and mucous membranes of the respiratory urogen and digestive tracts are really the main mechanical barrier the outermost layer of skin always sheds itself after a few days and so again we lose that top layer skin all the time and that's one way that we lose a lot of our microbes that get on us or we touch or we grab and those things will leave once we shed our skin okay so those are the transient ones we also have the flushing effect of the sweat gland so when we sweat not only does it cool us down but it helps wash away the microbes as well okay the blinking and tearing up of our eyes if you know anytime you get anything near or remotely close to your eyes you instantly start tearing up and that is a natural reaction because that's a way that we clean things out and so those tear have enzymes like Lyme which will break down any microbial matter that gets into our eyes and again that flushing the constant tearing up is a way to wash those eyes clean so that they're nice and and not sterile but at least microb free in that case Okay and then the stomach acid is another huge one again a lot of our systems are tied to the stomach acid so anything that we swallow goes to our stomach and that acid pretty much kills most things now there are some things that can make it through that stomach acid but they develop mechanisms to get past it so but normal everyday run-ofthe-mill bacteria and viruses cannot tolerate the pH of that stuff I acid so that is a huge barrier to getting inside of us as well okay so those are some of the first line of defense now some other things you think about any opening that we have to the outside world we also have mucus membranes associated with those and again those are sticky tissue areas where things will land and collect and so they land and collect and that there's a reason for that is that eventually we get rid of those things so we either break off those layers we swallow those layers we do those different things and so so it's really a trapping mechanism so that's what those mucous membranes are there for it's not just so that you can cough up wonderful Flem or you know have crusty boogers or anything like that the reason for all that stuff is to trap microorganisms so that eventually we can get rid of them either by sneezing them out coughing them out or swallowing them okay and so that's the end also nasal hairs the cyia and her trachea are also responsible for again filtering the air that we breathe also the Cy helps filter out our lungs all the stuff that we breathe and that passes it up so that we swallow it we swallow it in the middle of the night and then we pass it through our digestive system which the acid will kill everything so that's kind of how those guys work and how we see these mechanical barriers all working together okay some other things that are non-specific that are chemicals we think of sebaceous secretion so the oiliness of our skin there's a reason for the oil again it impedes microbial growth Lyme I talked about that in her tear it's also found in her saliva helps break down bacteria the high lactic acid and electrolyte concentration in sweat so sweat is good it's antimicrobial because it will the high salt concentration kills a lot of the bacteria that gets on our skin again the Skins acidic pH also plays a role so only certain bacteria that can tolerate a high acid concentration can actually live on our skin the hydrochloric acid again we've discussed that the hydrochloric acid very strong pH again strong acid destroys most vegetative bacteria digestive juices and bile of the intestines now this is closer to a ph of 7 however these have Micro microb estatic properties which will actually limit the number of microbes I grow the fluids like semen have antimicrobial chemicals added to it so you're not passing certain uh bacteria along and then again the vagina itself has a very acidic pH which can be affected by again hormones menstration cycles and things like this so again we see different populations during different times of the month different years and things like this and that's all due to the chemistry of the the female at the time so that's kind of how that works okay so lots of mechanical barriers that keep things from actually getting into our system so you think of any opening to the outside world there's typically a mechanical barrier there to block these things from coming in okay now another thing that doesn't get discussed a lot are genetic defenses now some people are genetically more viable than others and again there's a there is a reason or there is an idea of the good genes survive out because some people are more resistant and this could be due to not having certain receptors that are there so some people might look at as as a mutation however this could be a good mutation where if you don't have this receptor the virus can't bind the virus can't get in so now you're protected so you you don't have that way for the virus to get in so there are some situations good example of this HIV there's about 1% of the population that can't get infected with HIV because they lack the right receptor for it to bind in the receptor that they have that the HIV uses to get into the cells isn't working as well as a normal receptor does and so some would call that a mutation that could be bad potentially bad if it's an immune system however it actually is potentially good because it prevents you from getting HIV so that that's something that we we kind of look at and sometimes we kind of push off but there is truth to the matter that some people just in their genes alone seem to do better than other people and you've probably seen this in your everyday life you see some people that seem to be sick every time you know every time you run into them they have a cold and other people never get sick and some of that has to do with their genes that they have so they just have the right combination to be healthy all the time and that microbes just don't affect them as well so again does play a huge role so sometimes it's the genes you get from your luck of the draw the genes you get from your parents as well to determine your health okay so which of these is not an example the first line of defense which one did I not talk about is it the white blood cells the Lyme the hydrochloric acid in the stomach the sneeze reflex and the silly in the respiratory tract what did I not talk about at all in this case okay if you said white blood cells you'd be correct so we haven't discussed the white blood cells they're going to be in the second line of defense these sit in the tissues and the surrounding tissues ready to attack if things get through that first line of defense so if you said white blood cells you're paying attention good job okay so let's move on to the second line of defense and again these are going to be associated with the inner tissues so if microbes somehow make it past their first lineer defense they get entered in maybe they get through a cut or we you know swallow them in and somehow they get in or we breathe them in and they get into our lungs what is our second line to take over for where the first line left off and so that's what we're going to look at and again there's lots of different things that play a role here okay and again it's a large complex diffuse network of cells fluids that penetrate every organ and tissue so it kind of surrounds all the tissues and organs in our body and again we have really four main uh classifications or subdivisions of these things the first one is a very long hard word which is called the reticul endothelial system try and say that four times that is basically all your connective tissu so you have cells that sit in the reticular endothelial system and those cells are ready and activated ready to attack when anything comes in think of right under the layer of your skin you have a lot of connective tissue in that so if microbes break through through a cut in your skin you have cells that are just waiting there ready to go after these pathogens that have made it through the skin okay likewise and tissues surrounding the heart and other and other organs we have cells that are ready to attack of microbes make it into that area and so that's one of the things another one is the extracellular fluid the extracellular fluid is a big important part again that's all the fluid that leaks out of our vessels this contains a lot of white blood cells that then go and attack and find the foreign material that isn't supposed to be there obviously the bloodstream plays a huge part of our uh second line of defense because that carries all our white blood cells to the spots that they need to go and then we're going to talk about the lymphatic system now some of you may know a lot about the lymphatic system others may have never heard of the lymphatic system before and the lymphatic system is actually a third set of vessels that we have in our body that carries all that extracellular fluid that leaks out back into circulation so we'll talk a little bit about that we'll talk about the lymph the lymph uh lymph vessels or the lymph channels and then we'll talk about these little areas that look like these tiny little beans called lymph nodes and why those are important think of security checkpoints and that's what those things are we'll look at that as well in the second line of the fence okay all right so let's look at these again we have the reticul endothelial system the extracellular fluid the bloodstream lymphatic system you can kind of see all of them working in concert here so if we think of the reticular fibers these are the fibers that connect all the organs together and that and again you have a lot of white blood cells that sit in those fibers waiting to attack if something comes in we have the extracellular fluid which is again outside the cells it kind of bathes the cells and again it comes from the vessels the vessels are leaky those things come out and this fluid protects and bathes the cell in all these different in all these different tissues okay you also have the white blood cells you have the bloodstream again the bloodstream brings all the cells all the fluid to those sites and so that's important and then in here it really doesn't show you but we also have lymphatic channels the lymphatic system which brings all this fluid back to circulation and so there will be I guess they do show these lymphatic capillaries these are these yellow things and again it's brings in the fluid and brings these things back to the heart and we'll talk about that as well so there's a lot of things going on so if you think about it the blood is where everything originates from it gets into the extracellular fluid you get into the reticular system which is basically outside the connective tissue that extracellular fluid kind of baths the uh the Endo reticular endothelial system and then that fluid gets returned back through lymphatics through the lymph nodes and then finally back into circulation where it goes back through and the whole cycle begins again so that kind of gives you an idea of what this whole thing plays out okay so let's look at the reticular endothelial system first or Rees and so again this is a network of connective tissues and really this tissue has a lot of hiding spots for these wonderful white blood cells to go in now we have a wonderful monuclear fosy system which is basically these cells that like to eat things and these monocytes basically camp out and hide in these tissues so if any microbes or formed material gets there they're ready to attack and so whether it's a virus a bacteria a fungus or even our own dead cells dead and dying cells they go in and they eat these things up and then spit them out for breakfast and that's kind of what they do and that's their idea of the again fighting the second line okay and again we find these things all throughout our bodies in joints interconnective tissue of our organs and all these other places and so these kind of bathe our organs and where we find find this second line of defense okay let's talk a little bit about the blood and again blood is where everything originates and again the blood is a whole blood when we think about the whole blood we have the liquid portion and then we have the cells the liquid portion is the plasma and the plasma is about 92% water it has this yellow kind of appearance and again if you spin blood down you can spin it into its different parts again you have the liquid that sits at the top you get this little fuzzy area in the middle which is the white or Buffy coat and we'll talk about that and then you have the red that sits at the bottom and again you can see this on the slide here the plasma The Buffy coat and the red blood cells now we call it plasma if we still have the clotting proteins in there and if you take out and you make a clot in the blood then you call this plasma serum so serum the only difference between serum and plasma is that plasma has the clotting factors the serum does not because you've made a clot beforehand but we're not going to worry about that we're not we're we're not worrying about um blood clotting in this point in time but again that would be something if you were going into looking at blood and in coagulation and that stuff that would be important but for today let's just concern ourselves with plasma and and kind of look at that now the other two parts of the blood again The Buffy coat is kind of this furry layer that sits in the middle and that furry layer is all your white blood cells again that it constitutes about 1 to two% of all your blood is the white blood cells and we'll talk more about what all those cells are here in just a minute but those again are your immune cells these are in there for surveillance they're in there to go to sites where we have infection or to get to sites where they want to hide out and so we'll talk about that as well we also then again the big portion about 50% of our blood is our red blood cells and those red blood cells are the ones that carry oxygen also in the red blood cells and you can't see them very well you wouldn't be able to um get them out very well are the platelets and the platelets are responsible for clotting or blood not only do we have clotting factors we also have platelets that are responsible for clotting Bloods blood and basically basically filling the whole if you ever have you know Cuts in your vessels and that stuff and that's again a clotting procedure so again that's kind of what we're looking at with the blood okay when we look at the blood the cells we talk about hematopoesis and hematopoesis or hopis I guess but it should be hematopoesis is basically the production of blood cells where does this take place it takes place in the bone marrow the bone marrow is responsible for making your blood so any component of your blood is made in the bone marrow and this is found in your long bone so your humoris your radius and alna your femur makes a lot of your blood cells and then you can also talk about your tibia and fibula those are also very important for making lots of blood cells again the marrow which is in the middle of the uh again the middle of the bone is where you have your stem cells these stem cells are undifferentiated cells that can def differentiate into any type of blood cell so it can turn into red blood cells they can turn into white blood cells or they can turn into platelets and so all these different things work out what we're worried about are the white blood cells so we're going to focus in on those first and then we'll look at the different the arthro sites in the platelets here in just a minute so the lucaites are your white blood cells we've already established that and you have two types you have the granulites the ones that look like they have granules and then you have the other ones which are the a granules sites so they don't have granules in them and so we'll talk a little bit about these different ones here in just a second so granulites are the ones that have granules a granulites are the ones that don't again I talked a little bit about stem cells this would be the stem cell sitting in your bone marrow and again it can go off into any direction making any blood so we call this a matap poic matap potic uh stem cell meaning that it can make any of the blood cells now some of them will go in One Direction and they will go and make your red blood cells okay some of them will go into another Direction and make platelets some of them will go down and make the granul sites others will go down and make mon ites which is an Aran site and then others will go and make your BNT cells so again think of it this way all your white blood cells all your red blood cells and your platelets come from one master stem cell now I'm not saying that there's just one stem cell that does it all but there's one type of Master hematopoetic stem cell that you have in your bone marrow that produces all your different types of blood cells and so when you go on like things like cancer treatment drugs and things like this this affects your blood because your blood are rapidly reproducing all the time your white blood cells your red blood cells what are the main problems when people go on Cancer drugs is that they will go anemic because they don't make enough red blood cells and then they have have a hard time with infections because their white blood cells are affected and that's because they all come from the same type of stem cell and so that can be an issue so kind of think of that that's just kind of extra material just added in but that's that's why you have so many problems when you go on cancer uh cancer treatment drugs in that because it does affect all these rapidly dividing cells again one stem cell controls all your different types of blood cells okay so we first talked about granulocytes now the granulites include things like neutrophils and neutrophils are about 55 to 90% of all your white blood cells so if you go back to that tube of blood and remember I showed you most of it was Plasma on the top some of it was the red blood cells or it was about 45% plasma 55% red blood cells and about 1% of the white blood cells that Buffy coat and out of that one to two% of The Buffy coat 55 to 90% of those are actually nutrifil and those nutrifil are basically these indiscriminate cells that just go and eat their job is to go around and chop things up just like a Pac-Man wood on a video game so it just goes around chop chop chop chop looking for pathogens okay looking for pathogens or things that shouldn't be there and so their job is to go find foreign things and eat it and so that's the neutrophils okay so that we just associate them with phagocytosis another type of cell that you have and it's a very small percentage of cells that you have are about 1 to 3% of again that 1% of white blood cells are called eosinophils now eosinophils are specifically against eukariotic parasites so if you get infected with a UK cartic parasite say you get a uh protoo so you drink dirty water and you get a protone or you get a worm like a tapeworm or something else your eosinophil count will actually go up and that's one of the ways that doctors can figure out that you have some type of UK cartic parasite because if they see on your blood count that your eosinophils are high that says directly aha you guys have a parasite so you need to figure that out so that's why it's important to do these white blood cell counts to kind of figure out what type of infections going on the type of white blood cell that's raised up can tell you a lot neutrophils go up when you have a bacterial infection you know cils go up when you have a parasite infection now the basophils are even a small smaller percentage of cells and these are really geared to and again there are some reasons why we have these cells but we're really going to talk about these guys is in chapter 16 when we look at allergies you can blame the basil fills for your allergies because these are the guys that release their histamine and lucat trines and everything else and cause you to have an allergy reaction and that can be a bad thing and so that is what causes you to have those allergy responses those are the basophils so the basophils are why you get the allergies and we'll talk about about those again in chapter 16 and how you get an allergy attack and response okay all right now we have some that are aganos sites and again we have the B&T cells and this is about 20 to 35% of our white blood cells again out of that 1% and these B&T cells again are for the third line of defense so we'll talk more about these in chapter 15 we'll spend some time talking about how they get their receptors what the receptors are and how they get specificity and so again we think of B cells and antibodies t- cells and their t- cell receptors and again this is their specific uh thing and we'll look at this again in chapter 15 the last one of the aytes are the monocytes so these are very similar to what the nutrifil are okay nutrifil remember are the little Pacman that go around and eat well the monocytes will do the same thing they'll go around and eat pathogens however their responsibility is then whatever they eat they're going to show it to the BN cells so I like to call the monocytes or the macrophases the link between the innate immunity and the Adaptive or required immunity because these cells are responsible for eating things up in in the innate system but then they turn around and then they present to what they ate to the teac cell and say look what I ate you need to do something about this so they're kind of the early warning to get the acquired immunity started now there's always a delay with the acquired immunity and again we'll look at this in chapter 15 and the reason for that is that the macrophases have to eat something first in order for them to respond to the tea cells so it takes some time for the system to get going and so that's why you have that delay and so monocytes are very important to link the innate immunity to the acquired immunity and again we'll look at that link again in chapter 15 all right now we also I mentioned briefly about the arthro sites these are your red blood cells and again red blood cells lose their nucleus and the reason for that is because they they don't need to replicate anymore once they get to the red blood cell stage all they're going to do is carry oxygen and that's their lifespan once they've done that the cells die they go to the spleen to die and that's it okay and so these cells don't replicate once they get to that stage and so since they don't need to replicate anymore once they get to the arthrite they lose their nucleus so these are kind of the donut shaped cells when you look at a blood smear you can see down here these guys are all the red blood cells they have no nucleus when you look at white blood cells they stay purple because they do have a nucleus platelets also stain a little purple because they have little splotches of nuclei in them as well now the platelets are elements to clotting the blood and again these come also from the stem cells these come from mego curiosites these are like pieces of cells that are used to fill up holes when your blood vessel ruptures and so when you have a cut or an injury to the vessel these guys respond by plugging up the holes so that you don't bleed to death and so the platelets are really important for blood clotting and that's about the extent that we're going to get into today now there's some other rules for platelets and that stuff that it could go into and and really bore you to death with but for today we'll just think of them as a clotting mechanism okay they get activated and they plug the hole think of it that way all right so that's the platelets all right now let's talk a little bit about the lymphatic system lymphatic system is the third set of vessels that we have so we have the arteries which take blood away we have the veins that bring the blood back and then we have the lymphatic system lymphatic system is a series of vessels that carry fluid that leaves the vessels and again I told you the vessels are leaky and carry these vessels back to the heart so it brings the fluid back to circulation and so it provides an auxiliary route to return extracellular fluid back X is a drain off system for the immune system and again we'll talk about why that's important and again what it does is it renders surveillance for all the fluid that goes around so there is a way to monitor what's in your system and so the lymph system is very important for surveillance and looking at things that get out of the blood and are actually in your tissues so if it gets under your skin those things get picked up and get brought back and surveyed so that they know exactly what they're dealing with and we'll talk about that as we go through the lymphatic system so lymphatic system is necessary for bringing fluid back to the heart okay now again lymph is any extracellular fluid that leaves the vessels and it kind of gives you this yellowish green color and again it's very similar to what plasma is it's got some components of blood again it's made up of water dissolve salts and some proteins and so that's what gives it its color and again it's just any extracellular fluid that leaves the blood vessel okay what does it do it transports white blood cells fats cellular bre and infectious agents throughout the system so one of the things I didn't really talk about is that again organisms can use this as a basically a highway system to get anywhere in your body so they can use the lymph system to go from one place to another another place that we see this is with cancer so cancer is notorious for using the lymph system from going to one organ to another so a lot of times when you hear about breast you know breast cancer and that what they'll do a lot of times is remove some tissue for a biopsy and they'll also look at the lymph nodes that are found in the armpit the reason for that is cancer breast cancer especially likes to use the lymphatic system to go to other parts of the body so what they're doing is they're actually looking at the lymph nodes there to see if any cancer cells have actually made their way there if they have then they know that the cancer is trying to spread and that allows the doctors to know oo this is something we need to really be aggressive about and so that's one of the issues with the lymphatic system so that's another thing think of this highway system where things can you utilize it to get around around the body and we'll talk about that as well okay so lymphatic vessels are capillaries that permeate all parts of the body except the central nervous system however that's not true they are actually finding lymphatic system in the brain as well so this is old research the new stuff that just came out last year shows that we actually have lymp vessels in her brain okay bone placenta and thymus it has thin walls that allow for that can be permeated by extracellular fluid so the fluid can come into these vessels and anytime we move we move lymph fluid back to the body okay and again the function is to get the lymph back into circulation any fluid that leaks out has to get back into circulation somehow and these vessels allow it to go back into the system now you may notice in this picture here you see these little bean-like structures these beanik structures are called lymph nodes and lymph nodes are basically checkpoints to see what's going on in the fluid so basically the lymph nodes can look survey the fluid that's going by and say do we need to do anything about it because a lot of times microbes will be found in this fluid because it's got into the extracellular fluid it then gets into the lymph node and you actually have white blood cells macras B and T cells that are all sending in that lymph node ready to attack and they're essentially sitting there waiting for the right thing to come along so they can go and attack the thing that comes by so think of it as like a checkpoint or a a border crossing type of thing this fluid gets checked and if it you know they find something it's going to react and you know when these things react because then the lymph node swells and that's what you feel in your neck okay so that's the function of the lymph nodes essentially okay so again the extra solid fluid leaves the vessels and again A lot of times through the capillaries the fluid makes its way back into the lymph system that lymph system will take it back now again I talked talked about the lymph nodes already these are these bean-shaped uh I wouldn't say organs but these nodes that again the fluid comes in and you have these packed with different types of immune cells B cells t- cells and macrophases and these guys come in and they survey the fluid and if they find anything they get activated and they start to attack what's in here and again they send out the warning signal the rest of the fluid makes its way back and eventually it will feed back into circulation and that's the idea of a lymphatic system okay all right now we have two types of lymphoid organs we have the primary lymphoid organs and the secondary lymphoid organs the primary lymphoid organs are things like the bone marrow and thymus so when we think of primary think of where white blood cells are formed okay white blood cells are formed in the bone marrow all our white blood cells are formed there and then the thymus is an important organ for or gland for maturation okay so the bone merrow allows for the B cells to mature and get the receptors the thymus again the te- cells are made in the bone marrow and then go to the thymus to get receptors and that's important and so you get these te- cells that now have receptors on them and they're ready to go and so that is those are both primary uh lymphoid organs now when you're a baby your thymus gland is very very large but as it as you get older and you get into puberty it shrinks it starts to shrink even more by the time you 70 and 80 years old you have really no thy gland left and so again that plays a role in your overall immunity that's why as you get older and older your immune system goes away because your T cells aren't being as aren't being as activated and matured anymore because you're losing that thymus over time now the other organs that we have are the secondary lymphoid organs and these are wherever our white blood cells go and hang out and so we have these lymph nodes again those are where B&T cells sit we have our tonsils which are basically glorified large lym nodes we have our spleen and we have some other areas around our intestinal system that also acts as a lymph system and reg you know basically a surveillance system area so all these different tissues that have the white blood cells just sitting and lurking are called L secondary lymphoid so we have the primary and then the secondary and I think the next slide we'll talk a little bit more about that as well so the primary are your bone mirrow in your thymus okay these are where the the cells are made and matured Okay so bone marrow makes all the cells but bone marrow matures the B cells the thymus is where the t- cells mature and again we'll look at that in chapter 15 but those are the primary so either made or mature there okay the secondary are where the uh white blood cells go to hide and so that's a big thing so the lymph nodes the spleen and these other areas that are around the body and so again these are looking for these are for surveillance and so they come in and Survey the area and so these are the secondary lym noids okay so primary is where they are made and go and mature the secondary is where the white blood cells go and hang out okay okay so we have the te- cells the te- cells mature in what the lymph noes the spleen the thymus or the Gul let's see if you can think of that one the te- cells mature in the thymus so again we talked about that that is a primary lymphoid organ the te- cells get The receptors there and they mature at that spot so that's where you're going to see the te- cells okay te- cells mature in the thymus and that's actually why they're called t- cells because of the thymus okay so if you got thymus good job you're paying attention to the second or the primary uh lymphoid organs okay so now the the rest of the lecture we're going to spend some time just talking about how the white blood cells do what they do so we're going to look at inflammation phagocytosis interferon and complement so we'll look at those four things and this is basically how the white blood cells do what they do okay so the first one is going to be inflammation now inflammation is a response this is basically whenever anything gets in and your white blood cells attack so think of this as the innate immune response okay this is a response that takes place these are the classical signs you get redness warmth swelling and pain the reason for this the redness is due to the vasod dilation so this is where the blood again more blood to the to the injury the blood then leaks out okay so that's get the redness the warmth is again from the vasod dilation more blood to that area the swelling is due to the Leaky fluid the fluid again contains the white blood cells that are going to help fight the infection and then pain is due to the swelling because it tickles the little nerve endings and causes the pain and so you get those all Associated and so you've probably seen you know different examples of this so if you prick yourself and let's say this little Thorn The Thorn Cuts you you get more blood to the site to again uh take care of the w wound and that stuffs you get the redness and the swelling or the swelling here the tumor okay and then you get the rubor and calore which is basically the redness in the color and the Heat and then you get the pain which is associated with again the tickling of the nerve endings due to the swelling and so those all play a huge role in the inflammatory response so visually what happens in inflammation so let's say you get poked by either a needle or a nail or a pin and so what happens is these guys are coated with bacteria we know this again you guys did this in the lab looking at all the stuff that's out there the pin comes in breaks the skin and it brings a nice dose of bacteria into the body the bacteria get in you get a rupture of the vessel okay so the first thing you want to do is make a clock so this is where your platelets your other clotting factors all play a role so you don't bleed to death so that forms the clock Meanwhile your neutrophils are the First Responders they go in and they're saying oh injury let's go eat eat eat eat and so what they're doing is they're there to eat and so they leak out of the blood vessel and they go and eat all these wonderful little green bacteria so that's what you see now you get swelling associated with that as well so this is not only the fluid that leaks out of the vessel that could be leaking out because of the injury or just in general the inflammation but you also have cells you also have pus formation and pus is basically the waste product of the nutrifil so neutrophils are eating up and and basically digesting these bacteria and then this is the waste that is from the digestion of the bacteria so pus means that your immune system is working well and it's cleaning that area out of the bacteria now eventually what comes in are these very large macras and again these are going to be important to stimulate the T cell and V cell response so they come in and kind of finish up the job that the neutrophils leave off and so these kind of guys kind of come in and take the credit at the end and clean up the system they get rid of any remaining bacteria and say hey te- cells let's respond to this let's make memory to this and so will eat it and then they'll present it to the te and V cells and say let's make some memory so that we know that the next time we get this we can fight and those are the major events of inflammation so you get the injury you get the swelling the redness and and um warmth due to the blood the blood leaving the vessel the swellings due to the fluid that's leaving the vessel along with the cells eating some pus formation is due to the digestion of the bacteria due to the neutrophils and then finally the pain is associated with the tingling of the nerve fibers so all all these different things are going on uh during the signs of inflammation okay and that's really what happens during an injury all right so some other of the things that the white blood cells can do is even when you don't have injury is these things can leave the blood vessels on their own so they don't need an injury to the vessel in order to leave they can do what is called dipitus and dipitus is basically the movement out of blood vessels and you can see here these wonderful little white blood cells down here can actually either work their way through the either the middle or basically the the openings are in between the cells they work their way in and kind of force their way in and work and you can kind of see this happening and this is called dipitus and force their way through the cells they actually even can go through the cells too there's actually some um research that's been done that shows that white blood cells will actually even go through the middle of cells sometimes if they have to okay so this shows you that the blood vessels even though they look like tubes are not a solid structure that things can actually get through and again what brings in there is the chemotaxis so cells that are already present will release these chemicals to say more cells come to the area area and take care of this infection and so you get this going on all the time and so it's kind of an early response warning and that brings more cells and more cells come in and finally once the infection clears you're free of the pathogen okay and so that's what goes on in these situations okay now another thing that happens is fever fever is a normal response to when you have an infection and so anytime your body knows that it has uh foreign material in it it will send a signal to the brain to say let's warm it up and so what the warming is supposed to do is remove the pathogens from there and anything that causes or triggers fever we call pyrogens so think of phyro pyro pyrogens stimulate heat and that is due to the chemical response that triggers the hypothalamus to turn or reset the thermostat in your body and bring up the heat now we have both exogenous pyrogens that are found on infectious agents so sometimes the microbes themselves will trigger and uh fever to occur and other times we have cyto kindes and other chemicals that will be released by our immune system to say hey let's turn up the heat a little bit to kill the to help kill these microbes and the reason why we do this is that we have some benefits to fever so a lot of times we associate fever and think bad o we got a bad fever we need to take care of it but a lowgrade fever lot L of times are actually very beneficial because what it does is it helps control the spread of the microorganism so one it can inhibit multiplication so that's always good to keep bacteria from growing it impedes nutrition so if you keep the nutrition from the bacteria they have a hard time multiplying and growing so that's good and it can also increase metabolism and stimulate your immune system so lowgrade fevers actually can be a good thing and so I don't want you to assume that all fevers are bad Okay so that's the one word of advice I can give is that fever sometimes is not a bad thing now obviously if a fever gets above 103 to 104 105 that's when you really have to be worried but if you have a low grade fever like 100 or 101 those are those are actually good things that means your body and your immune system is working and it's fighting off infection so again the next time you have a low grade fever you might want to restrain yourself from getting the ibuprofen or the Motrin and letting it take its course sometimes when we take medication it only is prohibiting the the effects of the healing process so just remember that sometimes that a low grade fever can be actually a good thing for you all right so one of the last things we'll look at is phagocytosis and again this is to eat up foreign material and so I have a couple videos to show you not only phagocytosis but the last thing in compliment and what phagocytosis is is basically to survey the tissue find these things and eliminate them okay so look around for these again microbes particular matter in dead and injured cells then to ingest them eliminate these materials and then take immunogenic information and pass it on so this is specific to the monocytes so you remember the monocytes are that link between the inate and the adaptive immunity and again what they do is they eat things and then they take the information and then present it to the tmb cell so that's specific to the monocytes these are more for the neutrophils and the monocytes up here one and two and neutrophils again just eat and just digest and that's all they do they don't present and so the monocytes are the ones that present the material okay so let's watch this video on phagocytosis and take a look at what these things really are okay and what happens in this process in phagocytosis phagocytes are attracted to the area of invasion by chemical products of the microorganism phospholipids released by injured mamalian cells or by components of the complement system the fosite moves into the area of invasion and then attaches to the microorganism the attachment is mediated by a variety of surface receptors including antibody lipopolysaccharide and complement receptors for example the c3b component of complement coats bacteria or other particles and then binds to c3b receptors on the fosite this process of coating to enhan phagocytosis is called opsonization the microorganism is then engulfed by the fosite into a vacu known as a phagosome vesicles in the cytoplasm called lysosomes fuse with the phagosome releasing digestive enzymes such as lysosyme and proteases into the phagosome the structure resulting from this Fusion is called a phagolysosome inside the fagol lysosome microorganisms are killed and digested finally the digested contents of the phagolysosome are eliminated from the fosy by exocytosis okay so again this video is showing you a little bit about how the bacteria eats the stuff it brings it in through endocytosis digest it through the lome so we talked about the lome in chapter 4 those are those enzymes that are in vacul that get released and digest and again this is a nutrifil since it just kind of uses the exocytosis to eliminate the the pieces and these pieces end up forming the pot and so that's part of the pus not only the extracellular fluid but any of the digestive waste products that you see from the nutrifil themselves okay so that's what we're seeing with phagocytosis okay now again some of the cells that are able to do this include the nutrifil and eosinophils remember the nutrifil they're primarily for bacteria these go in and eat up bacteria dead cells and other things and again they eat them process them and then spit them back out basically after they're done digesting eosinophils are for the eukariotic parasites we talked about that again you'll see when we have eukariotic parasites this number of eosinophils actually goes up and that's one measure to look at now the macrophases like I said these are the specific these are the monocytes these are the guys that once they leave the blood vessel they start to eat things up and these guys once they eat them they will digest them and then they will present them and so this is the important part that they will eat digest and then present to the adaptive immunity to the TMD cells so again we'll look at this again during chapter 15 looking at how the B&T cells get presented and we'll talk about what the role of the macrophases and dendritic cells so these are both the macrophases and dendritic cells if you're wondering what those are those are basically monocytes that have left the blood vessel and so they get different names and again they get a little bit different structures they have some different receptors and things like this but I just wanted you to be aware of those things okay okay now here is phagocytosis I think this is a really cool picture this shows you some nutrifil actually eating up the bacteria so that's kind of cool in that and what's going on here is again basically the neutr will find the bacteria through chemot taxis it will bind the bacteria up in The receptors it will bring it in and here comes a lome so that's called a phagosome that's kind of like the stomach of the cell these lomes come in release these enzymes digest the bacteria gets the parts and then the release of those residual debris and so that's where those things go and that's primarily the process of Phagocytosis okay so the phagocytosis is bringing these cells in digesting and then releasing them out and this would be a neutrophil since it's not presenting those cells okay now interferon is an interesting chemical and we talked about this during the antibiotics so was one of the last things we looked at during the antibiotics if you remember and this is a natural chemical produced in response to infection and a lot of times we see this in response to viruses and so this is kind of when a cell gets infected with a virus this kind of sends out the silent alarm to other cells saying hey we need to do something we're getting infected with viruses here and so interferon does a really good job of turning on these other cells and so it's a chemical that gets released it turns on other cells you can see there's different types that turn on different types of cells and these things respond to the infection and so this is kind of the silent alarm to say hey I'm being infected by a virus let's do something about it primarily we talking about phagocytosis this is the bacteria and other things getting eaten up viruses on the other hand we need to deal with them in a different way because they actually infect cells and so we'll look at this again chapter 15 plays a huge role with turning on the T and V cells and how to in and fight these viruses inside the cells but this is one of the ways that we do it is with interferon and again we're seeing this as well with cancer treatments as well again it's a natural uh molecule that we can add to turn on the immune system and so this is being used also to for cancer because immune system can help fight cancer as well so this is one of the new treatments that we see okay the last thing we're going to talk about is compliment and compliment is a series of 26 proteins that react to different uh signals in the body to say okay we need to destroy these pathogens and so a lot of these things get turned on through different mechanisms in the body some of these are through innate mechanisms and others are through the Adaptive or required mechanisms like antibodies and antigens and that stuff and so again I'm not going to expect you to know all these different proteins and how these all do what I just want you to know is what compliment is compliment is a series of blood proteins that interact with the pathogens and Destroy pathogens not only do they turn on the immune system but they also can destroy pathogens by basically putting holes in the pathogens okay and again there's different Pathways I'm not going to expect you to know the different Pathways and the proteins and that stuff I think in amp some of you guys may have been bounced over the head a few times about learning compliment and what it does but here all I care about that you understand is what is it for okay so if you understand that what it's for why it's there I'm happy all right and I got a video just to show you the compliment pathway here compliment consists of a group of serum proteins that activates inflammation destroys cells and participates in opsonization compliment can be activated by a number of different foreign molecules the complement proteins respond in a sequential manner producing a Cascade of reactions the major components are C1 through C9 named in the order that they were discovered not in the order in which they function the complement Cascade can be activated by the classical pathway or by the alternative pathway in the classical pathway C1 becomes activated when it binds to an antigen and antibody complex the activated C1 then Cleaves C2 into c2a and c2b and C4 into c4a and c4b c2b and c4b combine to form a protease called C3 convertase C3 convertase then Cleaves C3 into c3a and c3b in the alternative pathway antigens such as endotoxin polysaccharides or cell wall components react with c3b small amounts of c3a and c3b are constantly being formed from C3 but without activation they are soon destroyed c3b reacts with the proteins Factor B Factor D and properdin to form a complex called C3 convertase which Cleaves C3 into c3a and c3b both of these Pathways of complement activation follow the same sequence after cleavage of C3 c3a is involved in stimulating inflammation c3b reacts with other complement components to form C3 convertase which forms more c3a and c3b c3b also attaches to the surfaces of microorganisms phagocytes have a binding site for c3b therefore microorganisms with c3b bound to their surfaces are more susceptible to phagocytosis coating of bacteria to make them more susceptible to phagocytosis is called opsonization addition of properdin to C3 convertase results in formation of C5 convertase which Cleaves C5 into c5a and c5b c5a enhances inflammation and acts as a chemoattractant for phagocytes c5b reacts with other complement components including C6 C7 C8 and C9 to form a membrane attack complex this structure forms a hole in the cell membrane and causes cells to lice okay so this gives you an idea of what takes place with compliment and again I'm not going to expect you to know all the pathways and everything else what I would what I would really want you to get out of is is that you know that we have a system of proteins in our blood that actually will help fight against one turn on the immune system either by the simulation of inflammation or opsonization again we'll look at that in chapter 15 or being able to plug holes into or poke holes into the um bacteria cells and so that's really what I want you to get out of it again don't worry about memorizing all these proteins and everything else okay so if you understand what compliment is I'm happy so that's good all right so let's finish up with a concept check so which of the following defenses is most likely to be active during a viral infection so I talked briefly about this what do you think it is is it inflammation fever interferon or compliment okay if you said interferon you'd be correct so that was the chemical like I said that is kind of the silent alarm so when cells start to get infected with viruses they can send that silent alarm out to other cells and stimulate them and say hey I've got a virus inside of me let's do something about this and so interferon is a great component of that it's kind of like the self-sacrifice to save the rest of the team so this cell will die eventually because it's getting infected but it will send out a signal to the rest of the cells either to stimulate the immune system or the other cells to block the virus from actually getting in so very good if you got the interferon all right so let's summarize so Immunology is the study of the immune system and again that's looking at the different components of the immune system and what's made up of all those different parts and again we talked about how the immune system ser surveys findes and destroys so surveys findes and destroys if you know that that's pretty much immunology and it's a study of looking at those things and I could spend days and days and days talking about the Immunology okay what we had looked at today was the first line of defense this is the first part of the innate this is the mechanical barriers and think about anywhere that you have open you know portals of Entry you're going to have these mechanical barriers ready to basically protect those portals of entry from getting infections and so again these are the structures and chemicals that keep foreign Invaders out and this includes the skin mucus membranes tears wax sweat any of those things any of those chemicals that are produced to fight off microbes the second line of defense is the cells and inflammation again we talked about it it's really all the things surrounding the tissues and the organs and the second line of defense primarily looks at the white blood cells and those are the granulites and the A granulites and again we're not we don't think about the t&b cells yet that's going to be for the next chapter uh but everything else so the monocytes the neutrophils the eosinophils and the basophils are all important uh cells for the second line of defense the lymph and the lymphoid tissue are again very important for bringing back the extracell fluid that leaks out of the vessels again goes through the lymph nodes where surveillance takes place remember your primary versus your secondary lymphoid tissue primaries where the white blood cells are formed or mature so that's the bone Maro and thymus and then all the other tissues like the spleen the lymph nodes the tonsils and all those those are secondary because that's where the white blood cells go to hang out okay inflammation the four four things are redness swelling heat and pain those are the typical uh signs and symptoms that you are associated with inflammation so if you remember that you're good and then we talked about phagocytosis which is basically eating the foreign material and then spitting it out if you're a monoy you actually take those particles and you present them to the te cells and then complement is a series of blood proteins that will respond to infection in the body and so that looks at the second line now on this last slide I have here is just showing you a little bit about the third line of defense again what separates the third line of defense from the first two is that one it's acquired this is something that develops over lifetime so it's what you're exposed to either naturally or through vaccines that tell you what your what type of uh or what type of uh immune system you develop and again you develop specificity and so it's what you see so what you see is what you're going to respond to and again this deals with the B&T cells we'll talk about memory and all these other things in the next chapter Okay so we've come to the end of chapter 14 if you have any questions about anything please don't hesitate to ask uh send me email step by office hours uh you know send me a text whatever you need I'm happy to answer at any time and I'm glad that you're enjoying the videos and you know I'm glad that you're watching and I will see you next time