so moving forward with the blood we'll look next at leukocytes and platelets this term Luke refers to white so these are white blood cells and platelets we'll see are also sometimes called thrombocytes so revisiting this slide we're reminding ourselves that if you take whole blood and spin it down you will end up with something called the Buffy coat not the superlight watery plasma but not that heavy iron laid in erythrocytes in the middle you've got these moderately heavy and dense leukocytes and platelets so leukocytes first the function of these leukocytes is they play a role in immunity so defending against disease and that's done in a lot of different ways that we'll talk about they are the only formed elements that are complete cells because platelets are just little fragments of these bigger cells and erythrocytes are missing many organelles and they eject their nuclei so that they can carry more hemoglobin so leukocytes are the only intact cells there's not many of them less than 1% of total blood volume is leukocytes and they do this interesting thing called diuresis because unlike red blood cells these white blood cells need to go and fight infection anywhere it may be found in the body so that means they need to exit the blood and what will happen is in the case of some type of infection some of the early immune cells that arrive will release these signals and I'm not getting into a lot of detailed terminology here it's not really part of the class but these signals will eventually make their way into a blood vessel and create what I think of as kind of a like runway lights as these white blood cells are speeding past if they see these little signals these little lights they will know that they should land there crawl or head it's like foot to walk like a pedestrian so they will walk themselves down the edge of the blood vessel and squeeze out in between some of epithelial cells and then they can make their way to the site of the infection that process is called die epiphysis there are five types of leukocytes basophils eosinophils lymphocytes monocytes and neutrophils here these five are in alphabetical order and you could come up with some mnemonic device for that but there's actually a better way to sort these using the mnemonic never let monkeys eat bananas that provides the relative abundance of leukocytes it just means which one of these is the most common and which are the least common so neutrophils are the most common of all your white blood cells down to basophils which are the least common never let monkeys eat bananas and so as we go through the leukocytes over the next few slides I'm going to tackle them in this order but there's one other way you could have sorted these which we'll talk about and that's if you notice the the terms here three of these are ending in fill and sometimes they're referred to as the three fills or the other two end in sight so the three fills end in the term fill because fill means to love so like a bibliophile loves books and Philadelphia is the city of brotherly love these three fills love stain so when we look at his still histological preparations typically you see these pinks and purples because there are these two different stains that are applied to tissues to stain either more acidic or more basic structures so these three types of cells these three types of leukocytes they absorb the stain they love the stain a specific part of the cells that love the stain called granules so the three fills are also called granulocytes granulocyte granulocytes that means they have these granules the other two lymphocytes and monocytes lack granules so they are a granulocytes so then the question is well what are these granules that are absorbing these different colors things and so you can get very detailed with this and talk about the little peroxidase of the serie protease extracellular trap we're not gonna get into all that this is just to show us that this is just describing the granules in neutrophils and then there are other types of granules and these other leukocytes you can learn about this type of stuff in an immunology course for our purposes all we care about is the fact that each of these leukocytes fight infection in different ways some of them have special granules to help with the fighting and they absorb these stains in certain ways so we don't care about the details we just know that some of these cells have granules that are involved in making the weapons that they use to fight infection so let's look at them each in order in order of their relative abundance never let monkeys eat bananas n is for neutrophils neutrophils let's look at the name first neutrophils are kind of neutral in their love of the stains that we apply to these tissues so like if you look at this picture you see there's some purple and there's some red so those are the two stains are these H and eastings one is purplish and one is reddish neutrophils they have granules see those little dots inside the cell are granules that's cellular machinery some are more purplish and some are more pinkish that's why they came up with neutrophil as the name because they're kind of neutral some granules are absorbing the pink some absorb the purple these are the vast majority of your leukocytes they're fairly large compared to red blood cell but the major way to identify these is through the nucleus this is their nucleus multi lobes in this case I see four separate lobes they are attached to each other so you may see some strands connecting the lobes and usually you can like imagine some sort of funny face inside the cell from the nucleus yeah I can see it a couple ways so each of these types of cells we're gonna ask ourselves how are we going to tell it apart from the other leukocytes and here you can use size a bit but really that multi lobe nucleus and the neutral color it's not super purple out here it's not super pink it's kind of both in the middle somewhere those are the ways you're going to identify neutrophils what's the function of neutrophils phagocytosis they are going to go out and there's tons of them right and they're just kind of roaming through your body and they just eat up just about everything that they find lymphocytes are next so pretty common maybe a quarter of your leukocytes are lymphocytes they have this dark circular nucleus so very different than that multi lobe nucleus from neutrophils in some ways you'll hear this described is that you'll know it's a lymphocyte if you see a halo of cytoplasm or a ring of cytoplasm now keep in mind this nucleus is a little bit pushed to the side so it's not a complete halo or a complete ring but you know more or less you can you can see it there so these lymphocytes are mostly found in your lymphatic tissue which we'll cover um soon in this course some of them are cruising around in the blood but a lot of them are in these big clusters in certain places in your body and the function of lymphocytes is to provide what we call specific immunity and we'll be talking about that more later when we discuss the immune system but what we mean here is that a neutrophil is just kind of this like brawler you know it's a big beefy fighter that goes around and whatever it encounters it's gonna attack lymphocytes are more specific so if you get a flu shot what you're doing is you're training your body to fight against these specific strains of flu in that shop it doesn't have all flu strains it's just the ones that the CDC predicts will be the most common this flu season so there they're going to only fight specific strains of virus or bacteria etc some of them also produce antibodies we'll talk about that more later monkeys never let monkeys eat bananas so M is for monocytes giving more rare here less than ten percent of the population or monocytes I think of them as monster cells because they're really large and also that you shape nucleus or kidney Bane kidney bean-shaped nucleus reminds me of like maybe some little alien or Godzilla fetus growing inside an egg it's a monster site a monocyte what is the function of these monocytes they will also be discussed with the immune system in more detail because they will leave the circulation go into tissues and then they change and they become these macrophages which means big eaters so they're actually gonna work with the lymphocytes to fight against some specific strains of invaders in your body we'll talk about that more later eosinophils yose just like a retro refers to dawn like a sunrise so in this case we're talking about the red coloration like a red sunrise so obviously that's something you want to look for it right away you can really see those individual granules that have absorbed that red stain but you know sometimes the stain wasn't absorbed as well or the slide is old or whatever so that red is not always the best indicator but these this by Loeb nucleus is also good sometimes you'll refer to it as a pair of lungs right they're roughly shaped like lungs it should always be two and if you're looking at something and you think it I think it's red I think it's an eosinophil check for the lungs and that should confirm the function of eosinophils is to counter-attack against parasitic worms and if you haven't gone on youtube and looked up the videos of people having these worms removed from their eyes it's worth a watch lasses basophils very rare they do have an s-shaped nucleus but typically you're not going to be able to see it because these granules are stained so dark base refers to the more basic stain this purple stain things things that are more basic like nuclei get that dark purples thing but it's so too invasive fills to the granules get that dark purple stain so I can't really make out the nucleus the job of basophils is releasing a couple chemicals that are involved in the immune system histamine dilates blood vessels heparin limits clotting so histamine you may not know much about histamine but you probably know about antihistamines like if you have some sinus pressure boy in your face and you take an antihistamine you're trying to relieve that pressure and the pressure is there due to inflammation these blood vessels dilate because you've got some sinus infection and there are immune cells fighting and dying in there and attacking substances creating all this like waste products that inflammation is gonna bring extra blood there and it's gonna help clear out this battlefield and more blood means more white blood cells are arriving at the scene to help with the fight so that's the purpose of inflammation if you take antihistamines you are kind of taking away one of your immune systems weapons but you know if it also takes away your discomfort then okay that's what I would do heparin prevents clotting meaning well we do want to keep that blood moving in the case of an infection to arrive at that battlefield and to bring the white blood cells and to carry away the waste products bring can assist with that so where do all these white blood cells come from well if you remember learning about where red blood cells come from the answer was that there are pluripotent stem cells found in red bone marrow and all those blood cells are made there so leukocytes are also made in the red bone marrow from Florrie potential stem cells we learned this term hematopoiesis at the time - meaning the creation of blood cells and then we learned that you can say a retro poiesis is the creation of erythrocytes and so Toluca police's is the creation of leukocytes and if you want to get really detailed you could say lymphoma use this is the creation of lymphocytes and in fact that has been studied a lot like there's just one type of lymphocyte called b-cells and look at all the different pathways and intermediate stages that you can take just before you get a type of b-cell these cells make antibodies so it's very complicated stuff and again this is a immunology type of stuff here we're not really concerned with all that detail but this is why we're learning these more specific specific terms because they really do open windows in to very complex processes and here's some references again to the lymphatic system which we'll be talking about soon and we'll finish with platelets which are also called thrombocytes platelets are small purple staining cell fragments and they come from these gigantic cells called megakaryocytes so here's a little red blood cell here's this massive megakaryocytes all these tiny little platelets are flaking off platelets are involved in clotting your blood which we call coagulation and they're one of two structures that you should know about in regards to clotting the other being those fibrin strands that come from the fibrinogen protein is floating around in your plasma they're gonna work with the platelets to form oh there's a megakaryocytes supermassive the platelets will work with the fibrin to create like this net or this web and you'll be trapping red blood cells and trapping white blood cells and stuff in this web and this is how a blood clot is formed blood clots are also called a thrombus which is why it's kind of nice to know that the other name for platelets is thrombocytes because then you'll know anytime you hear a reference to thrombus in medicine that's referring to thrombocytes to platelets so this has something to do with clotting and in fact a thrombus is just the name for a blood clot and why do we care about blood clots well because when blood clots go bad you can have a lot of pretty bad consequences so like a stroke is what happens when your brain or portion of your brain stops receiving blood because you had this clot form and then the clot broke off and wished its way through the blood vessels and eventually got into your brain and got lodged in the blood vessel in your brain and that's why we call it an embolus is when a blood clot travels through the vessels and then get stuck and becomes stationary it's an embolus so obviously that's pretty bad news another term you may have heard of as deep vein thrombosis DVT this is a pathology that you want to prevent on like long plane flights by getting up and walking around and there's little exercises you can do and stuff you would think when you learn about these things you would you would do them but I don't but you should do them you should exercise on that plane because what can happen is when your legs are all compressed in these weird positions and not moving much you can start to form these little clots on the inside of your veins and the veins bring blood back to the heart and then push it into the lungs so any blood going through your veins is gonna be on its way soon to the lungs so in this case you could form a little little clot a little thrombus that could end up in your lungs block a blood vessel and now you've got like a pulmonary embolism now you've got a big problem that we won't get into here so those are leukocytes and platelets they make up the buffy coat of spun out blood and we've now covered all of the components of blood we'll finish with a look into blood types if you've covered this in microbiology that's great you'll see more about it in that class organ physiology we're just going to be kind of an introductory look at blood types including antigens and antibodies