Hematology | Leukopoiesis: White Blood Cell Formation

all right nin nerds in this video we're going to talk about lucais so like every video let's first off decipher what is lucais lucais is the so lucco means white it's our white blood cells right so lucco poesis is the formation pois is formation formation of white blood cells that's what we're going to talk about in this video is we're going to talk about the formation of white blood cells so let's go ahead and dive right into it so first off what we're doing here is we're taking specifically uh a section of a bone here

and and zooming in on it super super deep so we can see at the molecular and cellular level okay so where does this actually occurring again same place that it's occurring in arthropo and Throop it's occurring in the red bone marrow okay so within the epiphyses of the long bones is a good common place for that with the tabic right the spongy bone all right so we're diving in right in there and we're going to zoom in so let's get started all right so first off we have a stem cell for all of the blood

cells within the entire body what is that stem cell called that stem cell that we're going to start off with right here look at this guy right here this stem cell is called a hemocytoblast okay a hemocytoblast but they also can call it a plur poent stem cell um you can even call it a hematop poic stem cell I'm just going to put a hemo cyto blast okay so this is our stem cell for all the actual cells within the body what happens this hemocytoblast is constantly dividing and it's dividing into two different cell lineages

look at this so one of the cell lineages that it's going to form is what's called a myoid stem cell okay so it's going to form a myoid stem cell the other one that it's going to form is called a lymphoid stem cell okay so two different types here again what is this one right here we're going to say this is the myoid and this one down here is going to be the lymphoid stem cell okay so these are stem cells all right so now myoid and lymphoid stem cells right first off myoid can divide

into a bunch of different things real quickly what can it divide into okay so a myoid stem cell what can it divide into if you remember myoid stem cell it can divide into three different cell lineages one is going to go to form red blood cells one is going to go to form platelets and the other one is going to go to form what we're talking about which is granul acidic white blood cells and monocytes okay so what we're going to focus on is this step right here but we will do a brief introduction into

platelets okay but we're focusing on this one right now the granul acidic white blood cells and the monocytes so then what happens this myoid stem cell is going to start dividing it goes into two different lineages I told you right one is for the granul acidic white blood cells and one is for the monocytes but real quick how do we know how does this cell know to go into forming red blood cells how does it know to going into forming pelet how does it know to going into forming granul acidic white blood cells versus monocytes

it's all about the hormonal or chemical factors for example we already know that red blood cells depend upon EPO Orr potin right as well as the other nutritional factors platelets that pend what's called TP which stands for Throop we'll talk about that because it's made by the liver and the kidneys and granul AIC white blood cells and monocytes what do they depend on now we can focus on it okay so let's say that this step right here is going into forming our monocytes and this one down here is going to form the granul acidic white

blood cells so what does need what needs to happen in this step well we need specific chemicals we need ucan three we need interlan five and we need what's called a granul acidic Colony stimulating factors and the reason why we need a granul acidic Colony stimulating factors is because monocytes are a granulites what does that mean that means that they have granules but they're not visibly seen whenever you provide some type of right stain on them okay they do have granules but they're not visibly seen whenever with a right stain all right next thing so

these These are going to drive this step so what's the overall cell going to be then this cell is actually going to be a monoblast so what is this cell called here this cell is called a mono blast and then what happens is this monoblast it's now committed to becoming a monoy so what happens here this cell starts actually converting itself into what's called a pronoy so it's going to start turning itself into a pro monoy so his nucleus was getting it's getting ready to start forming these constricted shapes right so this is called a

pro mono site then what happens it turns into a monoy so then it becomes a monoy and then one more thing can happen this monite will go into the blood right so we're going to show it going into the bloodstream but when it leaves the bloodstream so we'll show that here in a second it actually goes out into the tissues and becomes a maccrage but we'll talk about that in a second all right so again what is this last one here this is a mono site okay we'll come back to this one next one myoid

stem cell what is this guy going to need in order for this event to occur he's going to need same thing interlan three interlan five but he doesn't need a granul acidic he needs granul acidic Colony stimulating factors granul acidic Colony stimulating factors there is other chemicals that the monoblast would need but we're not going to go into that okay we're going to just keep it very very general all right so these chemicals are needed in order to drive this process okay with granul acidic Colony stimulating Factor being one of the most potent effects so

now what cell do we have now we have a Milo blast so what is this cell here called this cell is called a Milo blast okay here's where we get to the good stuff the Milo blast what happens to him this Milo blast can actually go and divide into three different cell lineages so now he's going to divide so look at him he divides into three lineages here one of them is actually going to be of like a basophilic effect right so one of them is going to be more of a basophilic we're going to

talk about this one the other one is actually going to be more of an eosinophilic and we'll talk about him and the other one's going to kind of be a little bit more of the neutrophilic right the other one's going to be a little bit more of the neutrophilic and we'll talk about this one okay so again the myoblast divides and it divides into three different cell types this one up here they're now first off when they go from the myoblast they're going to go into what's called a for specifically myoblast they're going into what's

called a prosy so Milo Blaster was called a prosy but each individual one is different so we're going to call this one right here we're going to call him a bzo philic right Pro Milo site right that's that first one the second one is going to be eosinophilic and I'll explain what this means eosinophilic Pro Milo site and then the last one down here is going to be a neutrophilic neutro philic pro Milo site so what happens here the genes get activated within this guy this basa this basophilic Pro mocy and now it's going to

turn into a specific type of cell which is now remember when it goes from Pro it always goes to the next thing so prosite to a myosite so what's the next thing that's going to happen this basophilic prosite will then convert into a basophilic myosite so now the next step over here is going to be the basophilic myosite now the nucleus is starting to get ready to constrict but it hasn't constricted yet it's starting to form more of a u-shape at this point in time so now it's kind of u-shaped maybe might be u-shaped so

let's kind of show that here okay and then it might even have some blue granules that are being present okay and what do I mean by Blue granules that means if you apply a right stain what color would this actual uh granules show they would show more of a bluish color because they take up the methylene blue base so again what is this one called This is called a baso philic myosite now what happens to this eosinophilic one the ashic one same thing it's going to take up that kind of like a U-shaped that hasn't

completely segmented its nucleus yet and then it's going to take up these red granules which is going to be due to the red eosin acid so it's going to take up that red eosin acid so this is an eosinophilic myosite and then last but not least right is the neutrophilic myoy what happens to him again he takes up more of that u-shaped nucleus right and this is going to be called the neutrophilic myosite then what happens the basophilic myosite will conf will finish up that that actual uh u-shaped constriction so it'll start finishing up that

u-shaped constriction here so now this basophilic myosite is going to start finishing up that u shaped constriction and it'll take on a full u-shape a perfectly formed u-shaped nucleus so it's beginning to start within the myosite form again all of these are beginning to form I should actually make these a little bit bigger because they're not completely u-shaped yet at this point in time within the myoc site right they're beginning to form that u-shaped but then as they get ready to go into this next one they should now have a perfectly constricted u-shaped nucleus so

now what is this one here we have this one here we have this one and this last one we have right here right so now what it should look like it should be perfectly u-shaped perfectly u-shaped nucleus now and this one should have a perfectly u-shaped nucleus and then this last one should have a perfectly u-shaped nucleus so again they're starting to form that u-shaped nucleus within the actual myoy but they completely form form that contct u-shaped nucleus within this next step so now this is called called a band cell okay what is the difference

between a band cell and a myoy is that they complete that constricted form of the u-shaped nucleus so now it's a completely formed u-shaped nucleus so this is called a baso philic band cell what would this one be and again we'll have the nice blue granules in here this one will have the nice red granules and this one will would have the nice this one i' obviously take up and I'll talk about this again in in a second when we get to their functions the nutrifil would actually take up more of a blue and red

so again over here it would actually have a blue and red granules we'll show that though when we get over there so again what is this one called esic band cell and this last one over here is a neutrophilic band cell neutro philic band cell okay now we come into the final stage after this they take on their ending form their true form and this is when the nucleus completely constricts in segments so what does that mean that it's segments it means it forms multiple nuclei it forms multilobated nuclei or different shaped nuclei so what

happens with the basail the basophil whenever it nucleus segments and constricts completely to get rid of that u-shaped it can keep the u-shape but some of it can actually form a s-shaped nucleus so it can have a nice u-shaped nucleus like still or it can form an s-shaped nucleus so again that's the difference between this one it's segmented now that differs the band cell from this next cell which is now a basophil so a basophil is just going to have a segmented nucleus which can either remain u-shaped or it can take on a s-shaped so

this is a bzo Phil the eosinophil it likes to form a bilobe nucleus so if you look here at theophil he likes to form a bob nucleus it kind of looks like an old telephone pole or you can imagine as like glasses right it's kind of like cool right so again he has he takes up that red eosin acid and that's actually going to be our eosinophil okay last one here the nucleus is the best at segmenting he loves to segment into he's actually called a polymorphonuclear Lucy he can have three to five loes so

look what happens to this guy he has I'm going to just draw three loes here but he can have even more than that and again I'm going to kind of change a little bit from here so that we stay consistent when we get over here what kind of granules does neutrophils have what color do they take up and again I'm going to change the color but remember it should have been that color the whole time it would be he takes up methylene blue base because he has Affinity the granal have affinity for methylene blue base

and some of his granules might have affinity for red is an acid so he would actually take up more of a he would have more of a pinkish cytoplasm because it's going to be a neutral color between the acid and the base so it's going to be a nice pink color so again what is this cell right here called This is now called a neutr fill okay so what cells have we helped to form so far we now have over here the monoy right with no visibly staying granas but he still might have granus so

we have monoy here okay one more cell line and within this Milo blast and then we're going to go over into the lymol blast all right so what did I say before myoid stem cell can form granul acidic white blood cells monocytes and they can form plets we've already done red blood cells we already know earthres let's quickly do thrombo PES very quickly so again what's another cell that this guy can divide into he can also come into another cell lineage and what is that cell lineage called that cell lineage is actually going to be

forming what's called a what is this cell here called This is called a mega Caro blast a mega caral blast what drives this step just like what what drives all of these other steps thrombo potin so bear with me thrombo Po eaten okay and this is made by who the liver and the kidneys so the liver and the kidneys secrete Throop and Throop Putin drives this step right here here to convert the myoid stem cell into the Mega Car blast just like every other one we always go from blast to Pro to site right same

thing so what does this guy become next thing is going to happen is he's going to form what's called a pro megaros site so what's this next one let's call it a pro Mega cararo site then what happens the prega caros site will turn into a mega caros site and then what will happen from there so again this is called a mega cararo site and that Mega Cario site will then get converted into a what's called a platelet so then that's what we're going to go into in this next step so again went Mega Caro

blast prega caros site Mega caroy and let's draw this Mega carite right over here so we can show some room here so what is this one right here again this is called a pro Mega I'm sorry this is called a mega cararo site and this cell is huge he is very very very very big like huge Okay so we've done the mega caros site let's come back over here and let's finish up with the lymphoid stem cells all right so now what happens here lymphoid stem cell he thankfully he doesn't divide into too many different

cells we're not going to go over the uh the natural killer cells in this one but they could also divide but we're just going to do for right now we're just going to go into specifically our lymphocytes so now this lymphoid stem cell what happens to him he goes into forming what's called a lymol blast so let's draw that with let's do that um let's do that black actually so again what is this cell right here called This is a lymphoblast okay so lympho blast right here now just like everything that we've done so far

what drives this step same thing interlukin 3 interlan 5 but here's the big thing lymphocytes are a granulocytes so they wouldn't need Colony stimulating factors they would need a granul acidic Colony stimulating factors okay and this would drive this step right here okay so now now interlan 3 interlan 5 and a granul AIC Colony stimulating factors can drive the lymphoid stem cell to becoming a lympho blast now what happens that lymphoblast he's going to start undergoing some specific proliferation and differentiation and then he'll become specifically a prolymphocytoid a lympo site and then what happens with

the prolymphocytoid will then become a functional lymphocyte but not completely so let me actually rephrase that one of the lymphocytes will be functional at this point in time okay so now we have a prolymphocytes the blood and goes I'm sorry Le the bone marrow through the sinos capillaries and goes into the bloodstream where it will reside in other lymphoid organs is going to be the B lympocytes because that's the mature one right so there can be two cells here one is going to be the bosy B lympo site and the other one is going to

be the tmpy T lympo site the B lymphocyte when it leaves the bone marrow and goes into the Cota capillaries it's functional the t lymphocyte is not the T lymy will have to go to a gland a lymphatic gland or lymphoid organ a primary lymphoid organ called the thymus where it will mature and undergo selective processes and then get put into the bloodstream to go into secondary lymphoid organs we'll talk about that in more detail and Immunity all right bosy so where's it going to go these two cells are going to go out here right

so let's just show we're going to go over there and show these two cells coming out over there all right now let's bring all of these cells and put them into the bloodstream and talk about their functions all right so again what cells actually what cells are going to be leaking out of here monoy is going to be coming out here right so now we'll have a monite we'll talk about him first right so we'll have a monite right here that'll be the first one we'll discuss the basail the basail will actually come out here

he'll be the second one we'll discuss right he's got the s-shaped nucleus with the blue granules that stain from the methylene blue base right and then we'll talk about the eosinophil so then we'll talk about the eosinophil after that so again the eosinophil has Bob nucleus you can remember because it looks like he has like little sunglasses on right and he takes up the red easin acid talk about him then we'll talk about the neutr and if you remember the neutr whenever goes on the segmentation it can form polymorphonuclear lucites which means it just has

multiple loes so again here's your that guy right there right there's our multiple loes here let's even draw another one there and then again he takes up both the methylene blue base and the red easin acid so he's going to have more of a pink pinkish cytoplasm right and then again what's the other one the mega carite here here's where I want to say something real quick the mega caros site first off the capillaries that are present within the bone marrow are what's called sinusoidal capillaries so really important these are called sinu soidal capillaries okay

sinal capillaries these are very important because they're very very permeable large intercellular cffs well they're not large enough because the mega carite is a huge huge cell so when it tries to be able to squeeze through the cotal capillaries and tries to get into the bloodstream it actually gets stuck and then what happens is it actually fragments it explodes and when it fragments it fragments into a very very many cytoplasmic fragments what are these cytoplasmic fragments called now these cytoplasmic fragments are called platelets so that's what these are now all of these cytoplasmic fragments that

that Mega carite ruptured into is now called platelets okay so that's very very important to know the type of capillary so these are our plets we'll talk about them all right so again what were these cells also that we have to talk about the B lymphocyte this is the one that will go straight into the bloodstream right so again what is this one called here this is called the B lymphocyte and he will be functional at this point in time he'll go to mature even a little bit more though within the secondary lymphoid organs like

the um the spleen or the lymph lymph nodes or the tonsils and or the GT or The Malt so so on and so forth the T lymphocytoid organs it has to go to a primary lymphoid organ what's that primary lymphoid organ called that primary lymphoid organ that it has to go to First it overlies the heart it's in the inferior neck right it actually kind of sits within the media stum where the heart is it overlies the heart this gland right here this this lymphoid organ is called the thymus and we'll talk about this more

in the immune system but it has to undergo its maturation process so then when it leaves the thymus and gets put into the bloodstream now it's mature and now it's going to be called our functional or mature tlmy but we'll discuss these in more detail all right so now we've put all of these guys into the bloodstream that's beautiful isn't it it's not that bad so now let's talk about the function of each one of these very quickly so monocytes are super interesting because when they leave the blood and enter into the tissues they can

form macras which can be fixed okay or they can be free what do I mean by that so monocytes whenever they leave the blood so let's say they leave the blood and let's say they go into the tissues so let say now they're in the tissues okay so over here we're in the tissues they leave the blood they go into the tissues and now they become macras okay what is macras mean maccrage means it's a big eater it loves to eat all of the certain types of cellular debris and different types of pathogens right so

this is a maccrage macrofagos are very very good at phagocytosis so what's their good function fago cytosis and they're also great antigen presenting cells um I'm going put apc's it's very good APC so these are its functions it's a great fagite it's a great antigen presenting cell but what did I want to talk about before was this maccrage can go and get fixed into certain places within the body what are those places it can go you know it can go into your central nervous system and if it goes into your central nervous system it forms

a very permanent resident which is called micro Gia those are those specific types of Gile cells that are present within the central nervous system another one is it can get fixed within the liver so it can get fixed in the liver and these are called the cuper cells cuper cells okay then it can also go and get lodged within it can stay within the alveoli so it can go to the alveoli or the lungs and it can become alveolar macrofagos and there's more and more that we could do but we'll finish up here with the

bones and then the bones a whole bunch of monocytes can actually fuse together and when they fuse together they form very very interesting cells that love to resorb the Bone and break the bone down and that's called Osteo class so these can become very very uh many types of cells and we only did a couple there's even more that we could do but we're going to just stick to these ones okay so again what do they do phagocytosis and antigen present presentation right and they can be permanent residents or they can be free to roam

around within the lymphatic tissues what is this one called This is called a basophil all right basophils basophils they have these these granules and these granules that they contain have Heparin within it and we know that from hemostasis right so from hemostasis again what does it have these granes can secrete two things one of these things that it can secrete is called Heparin right and we already know what Heparin does it's a natural anti-coagulant enhances anti-thrombin 3 activity right what's the other one it can release histamines this is the really important one and what do

histamines do histamines are they love to regulate inflation inflammation how do they do that we'll talk about it more detail but for right now all they do is increase the permeability of the capillaries and they help for what's called vasod dilation to increase the blood flow but we'll talk about that in more detail just know that it's a part of inflammation all right what's this next cell here this next cell here is called eosinophil right so again we already said this this was a eosinophil and we know it's an eosinophil because it and when you

do the right stain it takes up the radius and acid what does this protein what does this cell love to do it loves to secrete proteins so it has these these granules that secrete two major types of very very toxic proteins these are very very toxic proteins one of them is called the cat iic peptide cat ionic peptide or protein and the other one is called major basic protein and what are these things designed to do they love to kill specific types of parasites or worms so they're very good at killing parasites so they're very

good at killing parasites okay parasites or worms right what else can they do one more thing we're not going to go into Super detail on this but they do play a role a very complex role in in allergies and Asthma and stuff like that which is a type uh one sight hypers sensitivity so it does play a role a little bit within type one hypers sensitivities but we'll talk about that when we get into the immune system just know it plays a complex role in allergy and in asthmas what's this next one nutrifil nutrifil are

awesome okay what can nutrifil do they can do so much okay these are the most abundant white blood cells and we'll talk about a dwc here last thing at the end so neutrophils they actually can do a couple things one is they're great fagos sites so what is one of the big things that these guys can do they are great fagos sites you know what they also can call neutrophils they call microf fages so what does that mean they're little eaters they're not as good as the macras but they're little eaters so they love the

phagocytose substances so they're great phagocytes right that's one function another thing that it can do neutrophils are willing to give up their life sometimes right so one thing that they can actually do is they can do what's called an when start to take in a really really Hardy bacteria or some type of very very uh strong pathogen that's hard to break down they might actually start releasing what's called free radicals so what do I mean they can take oxygen and they can convert that oxygen to what's called super oxide then they can take that super

oxide maybe even convert into what's called hydrogen peroxide and then from here you can get two different things you can actually go to form a hydroxide radical or you can actually go to form what's called hypochlorous acid so now all of these things here I'm going to circle them here superoxide an ion hydrogen peroxide the hydroxide radical is the worst one and hypochlorous acid this is a really really bad one too it's like bleach basically what can these things do they can damage DNA they can damage proteins they can D damage cell membranes which is

bad which is good for breaking down the bacteria or the pathogen but it's terrible for the nutrifil because it can actually kill the nutrifil as well by damaging its DNA it's protein in its membranes so what is this thing called right here this can do a process which is called oxidative or respiratory burst all right and then there's one more thing that these can also do and it's called Nets but we're not going to talk too much about that it's just they can release what's called extracellular traps where they literally release their own DNA and

chromatin material onto pathogens to tag them for certain types of enzymes like cathes and G all right that's that process now let's come to the platelets the platelets are easy right so these are platelets these are these tiny little cytoplasmic fragments platelets what do they do if we watch hemostasis we know what they do they play a role in blood clots so they help to be able to plug um blood vessels okay so they help to plug blood vessels to prevent blood loss next over here this is called a b lymphocytosis do B lymphocytes are

very very good at being able to get converted so they play R in humoral immunity and we'll discuss this in more detail in immunity but what you're going to just need to know for right now is that they can turn into these really really important cells here which are called plasma cells and these plasma cells can secrete antibodies and these antibodies are important for being or gam globulins to fight off certain types of foreign pathogens so again these can help to be able to secrete antibodies all right that's the function of the B lympocytes for

right now there's obviously more that we could do but for right now this is the simplest form of it t lymphocytes can actually divide themselves and go well they can form two different lineages actually three but we're only going to talk about two here one is called the T helper cells so the T helper cells and what the t- helper cells do is they help the bosy to turn into a plasma cell that's one thing they do and they can also react with antigen presenting cells they can do tons of things but for right now

know that they play a role within helping the B lymphocytes to produce antibodies the other one is called cytotoxic t- cells and these literally induce apoptosis of infected cells so these induce apoptosis of infected cells like virus infected cells or cancer cells okay so now we've gone over all of these cells in pretty great detail right obviously we're going into more of them in the immunity now what I want to finish up with is if you take a millimeter cubed of someone's blood you take a microl or millimeter cubed of blood how much percentage if

you do a dwc with what you get of each one of these white blood cells all right so here's a little uh pneumonic to help you to remember that right here it goes like this never let monkeys eat bananas all right banana all right so never let monkeys eat bananas I love minions all right so never let monkeys eat bananas so nutrifil how much do they account for that's what n stands for nutrifil they account for about 50 to 70% of the actual white blood cells lymphocytes account for about 20 to 30 so again how

much 20 to 30% monocytes count account for about 3 to 8% and eosinophils account for about 2 to 4% and then basophils account for about 0.5 to 1% so this gives you the relative abundancy from what's called a d WC differential white blood cell count will give you the relative abundancies of the white blood cells right and you can just remember never let monkeys eat bananas to give you the relative abundancy of these and then in haker we'll talk more about platelets and their values okay all right guys so pretty much in this video we

talked everything that we possibly could about lucis we discussed in detail the entire luoptic process and we talked about the functions of the white blood cells and the relative abundancies all right see you Ninja nerds