Innate Immune Defenses

welcome to this video on innate immune defenses when we use this word and Nate we're talking about an ability that you're born with so this doesn't have to develop from exposures healthy babies should immediately be able to have these defenses at work although they're not as strong as they would be in an adult so that's what this word and Nate means you were born with it baby and the real difference then that we should consider is we need to compare this with adaptive immunity and we'll be talking about that in a couple just a couple pages farther in our notes adaptive immune defenses those take time to develop and they only occur after exposure to a pathogen after exposure to a particular pathogen specifically their T and B lymphocytes are the driving cells for adaptive immunity and all the other white blood cells are associated with innate immunity although they might have a role to play and adaptive okay so that's our background and now I'm going to give you the different kinds of innate immune defenses so they can be divided into a few different categories first they can be physical or external barriers like unbroken skin and mucous membranes or they can be chemical and internal barriers and that would be things like inflammation anti microbials and something called complement and then the third category that we'll put on this page will be cellular fighters so we've highlighted all of those in yellow your innate immune defenses can be boiled down to three different categories physical external barriers Chemical internal barriers and cellular forces basically different kinds of white blood cells okay so let's go ahead then and start with the physical and external barriers we'll use a black pen and then highlight in green so the first one I'll show you is hair so yeah your hair is important to prevent infection whether it's the hair on your head the hair and your armpits pubic hair or the hair in your nose or the hair in your ears it all helps to say stay away so microbes actually might not even get to the surface of your skin thanks to that hair the next one well sorry we'll highlight this in green the next a physical barrier that all highlight is earwax so anytime you have a wax or a mucus it's going to be beneficial in trapping and preventing pathogens from getting inside so it catches and traps pathogens and then similarly mucus I'm drawing it here coming out of the nose but mucus is also on all of your mucous membranes inside your body and again this is going to serve a similar function to earwax to trap and inhibit pathogens it's runny ER in nature than earwax it's actually mucin as a protein that when it meets with water it swells up and forms the gel that you would recognize as mucus so here we can drop some mucus there okay then let's go ahead and add some here I'll use a blue pen and let's have some saliva coming out of this person's mouth now I'm switching back to my black pen to write saliva and what I think is particularly cool about saliva is like most bodily secretions it contains an enzyme called lysozyme that is able to damage the cell wall of bacteria now we can go over to this side of the head and oils are produced all over on our skin and they're important for two reasons number one they're going to lubricate the skin to keep it from cracking which could allow pathogens in but they also contain antimicrobial fatty acids then we'll highlight oils in green and let's get your blue pen and have some tears coming out of this guy's eyes tears are another bodily secretion that is able to inhibit pathogens and it does so in two ways number one we all know our tears are salty and so that is going to put osmotic stress on pathogens that have a hard time living in a salty environment because it makes them lose water and also lysozyme so if you put together lysozyme that damages their cell walls so that they can't keep the water in as well and then and then you put that salt on them then the water is going to leave the cells and hopefully kill the pathogens so let's go ahead and put this in green okay now we'll talk about stomach acid right here so stomach acid has a very low pH not surprisingly and that low eh damages most bacterial cells there are certainly some kinds of pathogens like h pylori that can live in a acidic environment and Listeria monocytogenes you know Denise is also capable of surviving through the stomach so let's put some hydrochloric acid in your ear it's the cells of the stomach that actually make this acid cells make in their parietal cells so they make the hydrochloric acid and you might remember from anatomy and physiology too that this hydrochloric acid is important in activating pepsin which is an enzyme that helps to start the breakdown of proteins in the stomach but it also serves the purpose of inhibiting pathogens so the low pH damages most pathogens and that's why there was rising concern it's pretty well understood now that it's not a good idea to take antacids if you really really don't need them because by decreasing the amount of acidity in your stomach you make your defenses a little bit less and there could be some more subtle effects like let's say someone doesn't get really bad diarrhea because they don't have enough acid but maybe now they start to get an imbalance in the flora in their gut and then that could have more subtle health effects and those sorts of things are being researched these days ok so now let's move down to this little lady right here she's going on a run and let me tell you she's going on a run so she is gonna sweat from those hairy armpits cool not only cool herself off but that sweat is important in helping to prevent disease so sweat is another bodily fluid that contains lysozyme and like a tear it's salty so very similar to tears it's salty and it contains lysozyme and we'll also use this running gal to point out that basically your best physical barrier against disease is unbroken skin and that's why band-aids are important it's why it's important to clean wounds because even a three-year-old understands that if they have an ally that that could get infected well I guess I don't know if all three-year-olds would understand that but mine did but maybe this because I always told them that so unbroken skin is your primary physical defense against pathogens and that's why oh and I was also going to say that that oil on the skin helps keep your skin supple and that is going to also help prevent it cracking so the skin is normally fairly dry and pathogens especially fungus like a wet environment so just that dryness is useful but then it's not so dry that it cracks the oil keeps it supple and this is why if someone maybe is washing their skin or their baby's skin too often it can actually damage the ability of the skin to have its normal flora and then that can lead to different kinds of skin infections so that's my third point I want to make is that the normal flora that means the normal microbes help to prevent pathogen colonization and you know there's always opportunistic pathogens on your skin like different kinds of fungus but as long as they don't over grow they don't cause disease so just keeping their numbers down and having everybody only have a certain amount of the opportunistic pathogen is going to help prevent disease so here I want to point out that there's normal flora on our skin and then what's also while we're at it put an arrow down here to these normal flora that are on this mucous membrane so I'm going to use purple for these bacteria maybe that means I'm drawing lactobacillus which is gram positive but you can just imagine lots of different normal flora the microbes that are in your gut and that brings me to the other primary defense of it's a physical barrier is going to be healthy mucous membranes so I'm going to write that right here under this mucous membrane healthy mucous membranes we can hear Pippen having a drink so my poor Pippen he's my Australian Shepherd he has had a relapse of what's called autoimmune meningitis and that would be a whole video to explain it but one of the treatments for it is just something as simple as prednisone which is a steroid and so when he's on that it makes him really really hungry and it makes him drink all the time so he drinks lots and lots of water and then has to go pee in the middle of the night poor guy well poor me too right I have to go take him out okay so let's this healthy mucous membranes and I want to remind you of where we find those in the body so there are basically five important mucous membranes the first one covers your eye your conjunctiva and you can go back up to where the tears are in containing lysozyme and that the tears help to keep that mucous membrane from becoming infected but that's why if it gets too dried out like let's say on a windy day someone can get conjunctivitis or maybe even pinkeye if they start to not have that protective mucus membrane doing what it should do and then the let's see if you can remember these could you go along with me so if I told you the respiratory tract then what would you immediately think of next probably the GI tract mucous membrane and then could you think of the urinary tract and then there's one more and hopefully you can come up with the reproductive tract so in males these two are combined because the penis has the urethra as well as that's the passage for semen but in females you're they're gonna have separate urethra and vagina and that brings me to my next point so get the blue pen again and the urine is very acidic and so our vaginal secretions in fact nobody could ever get pregnant if semen weren't very alkaline because it's so acidic in here that the sperm would never be able to survive ordinarily and so semen has to have a lot of alkalinity in it to help enable those sperm to survive so that I'm going to use my black pen and then just add that the urine and vaginal so this is going to be a low pH and same with vaginal secretions right here please both have a low pH and then why like that angry so urine and then vaginal secretions okay so we're ready to move on now to the second half of these notes this is going to be on the chemical and internal barriers so starting here I will first tell you the different types so first will be inflammation so you could use a black pen to write inflammation so that's an important part of the innate immune system and then if you can take your blue highlighter and highlight it and then your blue pen and put a nice box around that so inflammation and then scoot your paper down a little bit and these are supposed to represent antimicrobial galore so what I mean by that is your body makes so many anti microbials and that word galore tons of them a plethora of antimicrobial so that's gonna be the second sort of chemical slash internal barrier that I'll talk about and then complement and that's a funny word that basically means many chemicals working together compliment one another in their final job of fighting pathogens so I'm going to highlight that in blue and then put a box around it okay blue box okay so let's go ahead and go through these so inflammation right here your blood vessel and my classic blood vessel I'm showing some endothelial cells that when they become leaky or and that's what inflammation is all about water is allowed to leave and so water and white blood cells leave the blood vessels and enter the tissues and then they're able to bring nourishment and fight disease and that is what inflammation is all about so inflammation is when blood vessels become leaky and allow more water to leave than normal so bringing more fluids and white blood cells and I'll put WBC's for white blood cells to the wound if it's an injury or the infection site and then here I'm using your blue highlighter I'm showing here to be like a white blood cell that came into the tissue left the blood stream and went into the tissue to fight and then maybe we should also put here okay then next anti microbials I'm going to use my orange highlighter and just sort of outline these these are things like fatty acid and little peptides so my orange pen short-chain meaning they're really short as opposed to long chain short chain fatty acids can be antimicrobial and peptides that means either really small proteins or protein fragments and they have a variety of ways that they can disrupt the cell integrity of a pathogen and mess up their function and interestingly they are made a lot of the times by your epithelial cells in your mucous membranes so they're often made by epithelial cells and then maybe not so surprising that they're also often made by white blood cells okay next up complement so I'm going to use my blue highlighter and these are all little peptides and chemicals that are normally circulating in the blood and I use my black pen here so this is a group of circulating peptides again meaning they're really tiny they're usually most of them are made from the liver and when they are activated they sort of join hands and come together they stick they make like a hole in the cell membrane of a pathogen and then they mess up the cell membrane function so when activated form a membrane attack complex don't you love that membrane attack complex it reminds me of a show I used to watch when I was a kid called wool Tron where they were there these different like kids that flew different robots and then all the robots would come together to make one giant robot called Voltron that fought the evil evil in the universe so this represents when they're activated and all these chemicals come together like dundun dundun dundun and pop a hole in the cell membrane of poops cell membrane of a pathogen and when they do that then water can rush in and then lyse the cell so and if there's enough of these especially then the water will actually cause the cell to potentially blow up so we could put water may lyse the cell meaning make it break or rupture okay the other thing that compliment is going to be doing this is its most exciting role right making this membrane attack complex it virtually like or like just pops holes in the membranes of pathogens but also complement feeds back to enhance inflammation and phagocytosis so it makes macrophages more likely to engulf whatever they find so that's another role that it would have okay so the last thing we're going to talk about are the different cells that are part of the innate immune system and the easy way to remember this is that well if it's not a t-cell and it's not a b-cell then it is part of the innate immune system so what I have on here here is a I guess I'll also color this whole thing blue this is meant to represent and antigens that were taken from different things that this encountered so then this is called an antigen presenting cell you'll learn more about these as we go on in our notes but these antigen presenting cells can be either macrophages oops or what are called dendritic cells those are your two best examples there and they sample things that they find and then they present them to a t-cell or a b-cell and for that reason this is the link with adaptive immunity it's going to start it so if you don't have enough antigen presenting cells or they're not working right in your body then adaptive immunity might not even get started properly so that's the link there and then if you go up here another important couple of cells may take your purple highlighter and put purple dots all over this one and you might remember some point learning about basophils and mast cells and these mast cells in particular are very very very plentiful underlying mucous membranes in the tissues and basophils are a very similar kind of cell that circulates in the blood but they both release histamine and histamine causes inflammation it it causes the blood vessels to be leaky so this is going to be an important part of the innate immune response and not surprisingly also highly associated with allergies and other kinds of inappropriate immune responses okay then this next cell is natural killer cell and a natural killer cell is a lymphocyte as opposed to like a tea and a b-cell but it's considered part of the innate immune response because it doesn't have to be activated by an antigen presenting cell we usually call these NK cells and these are well known attacking virally infected cells and also tumor cells of cancers and like I said they're part of the innate immune system because they don't have to be activated the way a tea or a b-cell does okay then our last two this one right here is a neutrophil the neutrophil is sort of a jack-of-all-trades we have more of these circulating than any other kind of white blood cells they are phagocytic they can release bleach and peroxide they're sort of a jack-of-all-trades kind of useful white blood cell and then this last when the escena fills are very very rare and the escena fills are especially important in fighting off parasitic worm infections that said they are also like the mast and the Bezos filt mast cells and basophils strongly associated with allergies okay thanks for your attention for this pretty long video I will see you in the next one

Channel: susannaheinze

Views: 39,351

Rating: 4.9297218 out of 5

Keywords: Innate Immunity, physical barriers, chemical barriers, lysozyme, bacterial inhibition, antimicrobial substances, complement, membrane attack complex

Id: Vp9Ik_m7gFE

Length: 25min 17sec (1517 seconds)

Published: Fri Apr 12 2019