Introduction to Blood | Plasma, Buffy Coat & Hematocrit

hi everyone Dr Mike here in this video we're taking a look at an introduction to Blood let's have a look at all the various components inside of blood and what they [Music] do so to begin we need to remember that when we look at various tissues of the body that they sit underneath four major categories the four major tissue types are nervous which is there for communication muscle which is therefore contraction to perform work allowing for us to basically move so muscle for movement epithelia lines organs and lines structures and separates out one area from

another and then connective which anchors and binds and holds things together the reason why I'm bringing these four up is because blood is going to fit underneath one of these four which one what do you think well it's going to be strangely enough connective blood is a type of connective tissue now this is interesting because if I were to right blood underneath connective tissue and then list let's say two more different types of connective tissue bone is connective tissue right and so is cartilage so let's write this down we've got cartilage and we've got bone

now think about those tissue types bone is a solid we know that cartilage is a semisolid and blood is a liquid and taking a look at these three different types you would go well they're all connective tissue but what makes them connective tissue I can't see blood wrapping binding or holding anything together how is it possibly connective tissue well remember connective tissue is made up of cells and gels cells and gels and there's also fibers so you can say cells gels and fibers now it's the gels and fibers that change the consistency of the tissue

so for example with bone the major cell type that you have even though there's many are osteocytes so we've got osteocytes for cartilage it's you know what type of cells are in cartilage condra sites condra sites and then when we look at blood well there's many cell types but again you could argue that it's erthrocytes and let's just write red blood cells they're the cells but what about the gels and the fibers so here's the thing bone being a solid it has the Osteo surrounded by the interstitial fluid right there's always interstitial fluids surrounding cells

but the thing is with bone that interstitial fluid has things dissolved in it and those things include calcium and phosphate as well now when you've got calcium and phosphate inside of that interstitial fluid it makes it really hard but in addition to that it makes it brittle but we don't want bone to be brittle we want it to have some degree of flexibility so we're going to put some fibers in there like collagen so now what we have is a solid tissue that's really hard because of these inorganics this what we call hydroxy appetite and

collagen which gives it a little bit of bendiness but it's very solid with cartilage it also has collagen which is why it's got that bendiness to it but the thing is it doesn't have the calcium and phosphate inside instead of it's got basically carbohydrates and so what that allows for it to be is not a liquid but a semisolid a very flexible tissue now let's take a look at blood that's the focus of today the blood has in regards to what's dissolved in it well it's got things like solutes right so ions and nutrients and

wastes but it's keeping it as a liquid now what's the fibers that's in blood well we've got something called fibrinogen fibrinogen now fibrinogen is inactive it needs to be activated into fibrine and what that does is it allows for blood to form clots so this is that binding that we know of when we think of connective tissue The Binding and wrapping is the fact that blood can form clots and that's because of the fibers inside but when you look at blood it just looks like a liquid so yes blood is connective tissue just like bone

and cartilage because it has cells gels and fibers the liquid inside is what we call plasma and that's where I want to first begin in is looking at the components of blood so I were to take blood out of your vein for example and I stick it in a tube and I take this tube and I spin it in a centrifuge what it does is it separates out layers within the blood it separates out the components according to their density or their mass and what you find is there are three layers so let's have a

look at these three layers 1 2 three so we've got one two three layers of the blood let's start at the top and move our way down and have a look at these three layers and what they are this very first layer at the top makes up most of your blood so this layer up here its name is plasma so that's our blood plasma and that makes up about 55% of your whole blood remember if you're male you have around about 5 to six lers of blood in your body if you're female around about 4

to 5 L of blood but again this changes and is variable depending on age and Circumstance so for example if you're pregnant you're going to have a larger blood volume if you're an athlete you'll likely have a larger blood volume so those things need to be taken into consideration generally speaking your plasma 55% you've probably got around about 3 l of plasma in your body we think about it almost like there's about 45 Mills per kilogram of body weight so I'm 70 kilograms so that's 3 l 3.1 L of blood plasma so that's 55% it's

this straw color it looks a bit yellowish to it what's inside of our plasma well mostly it's water so if we have a look at what's inside of our plasma the first thing is that it's made up of water in actual fact 92% of that 55% is water what is important about knowing this well first thing that's important is we know that water is a boomer Ang when we look at it as a molecule and we know that the hydrogen of this Boomerang so two hydrogen one oxygen has a slight positive charge and the oxygen

has a slight negative charge this is important because water being a polar substance charged it likes other charged substances and we know that if something's negative it likes to be around positive stuff if it's positive likes to be around negative stuff and because hydrogen uh water has both positive and negative charges it loves positive and negatively charged stuff and that's important because it's going to be what we call a solvent it allows for things to be dissolved in it and it will follow any charges I'll get to that point in a second so 92% of

our plasma is water what else do we have well another thing that's present inside is going to be our proteins we have proteins in this blood plasma and that makes up around about 7% 7% of that 55% are proteins and there's many different types first protein I want to focus on which is the most abundant protein is what we call alamin now elamin probably makes up around about 60% of these this 7% of proteins I know we're breaking down these percentages most abundant protein in blood basically liver produces elbin and it plays a number of

roles two major roles that you should remember when it comes to elbin the first of which is it a carrier molecule it carries stuff the question is what does it carry well because blood is made up mostly of water lipid soluble substances like lipid soluble hormones fat soluble hormones or drugs really don't like just floating through the blood it needs to be attached to a carrier and that Carri is generally elbin so elbin will carry many lipid soluble substances and like I said these lipid Sol soluble substances can be drugs or they can be hormones

and they can be other lipid soluble substances within the body the other function of elamin is it helps maintain our osmotic gradient or osmotic pressure now your question might be what is this what are we referring to here osmosis is the movement of water across a semi-permeable membrane right and the way I think about it is that when you have a molecule that's charged remember proteins are mostly charged because they've got a phosphate backbone so elbin is carrying this negative charge with it now what did I say loves following charges water so wherever Elman goes

it pulls water towards it and that's osmosis so therefore elbin is really important in maintaining the osmotic pressure specifically the osmotic pressure within a blood vessel so remember this particular concept I'll quickly wipe this off just so I've got more room the concept is that of capillary exchange so remember that if you have a blood vessel so you got the arterial end and then you've got a capillary bed here and there's all holes in this capillary bed that makes sense because capillaries are the side of exchange and then on the other end we've got the

Venus end of the capillary bed there we go and again holes here and what we know is that we've got tissues outside of the capillary bed and as the blood moves through we need to push substances out so what we're pushing out to the tissues here to be fed are going to be things like oxygen and nutrients right but the thing is the oxygen and nutrients they're dissolved in the water they're dissolved in the plasma so plasma gets pushed out fluid here's the thing this happens at all the tissues of our body if we keep

pushing plasma out we're going to lose our entire blood volume within a day so we need to find a way to reclaim this plasma and the way that we reclaim that plasma or pull it back in is because we have negatively charged elbin that remain inside I'll write a here negatively charged Elmen that remain in the blood vessel it's too big to move out of the capillaries so as the hydrostatic pressure the blood pressure pushes stuff out on the arterial end on on the Venus end it's pulling stuff back in because the elban has a

negative charge now that's important clinically because I said your liver makes elamin so what if your liver isn't functioning very well you don't have the elbin you don't have the elbin you can't pull this fluid back in the fluid remains out in the tissues and that's what we call edema so again the osmotic pressure here the role of albumin in maintaining osmotic pressure super important so that's Albin as a protein there's a couple of other proteins that you should be aware of and we'll go through them quite quickly are the globulins so globulins are these

proteins and there's a couple of different types of globulins so there are uh Alpha and beta globulins but we also have gamma globulins as well what are the differences well couple things Alpha and beta globulins they do a bunch of stuff predominantly they're similar to elbin in the sense that they are carriers and they carry lipid soluble stuff but they also carry metal ions so they carry things like copper and iron so not only do they carry fat soluble stuff but they carriers of metal ions they can also play a role in inflammation but let's

just forget about that so they're the alpha and beta globulins gamma globulin you've probably heard of before like imunoglobulin G these are antibodies right and so these antibodies we know are produced by our B cells ultimately the B cells turn into plasma cells and they produce these IG antibodies in another video where I talk about hematopoesis and also the immune system I cover this so we've got globulins inside of our blood plasma as well and the last protein I want to refer to before we move on is that of fibrinogen fibrinogen I spoke about it

before what did I say fibrinogen does it allows for us to clot so this is also made by the liver many proteins are and it's inactive it needs to get activated by chopping off that OG GN if you want to understand more about fibrinogen and its role in blood clotting I suggest you watch my hemostasis and blood clotting video that covers all of the clotting Cascade and hemostasis that you need to be aware of so these are the proteins present within blood that's not the only thing present in plasma the other thing we have in

plasma which is making up pretty much the final what 1% is solutes now solutes is a generic term meaning anything dissolved in a solvent what's a solvent water is a solvent water is the biological solvent and things are dissolved in it things dissolved in it generally are polar so have a charge to it or they're very small and so the types of solutes you're going to find inside of your blood include things like ions nutrients waste hormones gases they're the major solutes that we're going to find inside of our blood PL so ions what am

I referring to when I talk about these ions remember they're charged atoms or elements things like sodium pottassium magnesium chloride hydrogen ions bicarbonate ions phosphate ions you know there's a whole bunch right so these are ions just charged atoms or elements why are they important inside the blood they're important because their quantity determines water movement as well that's why we have electrolytes electrolytes are really important because they determine fluid balance maintaining blood volume these ions are important but that's not all they're important for we spoke about calcium is also another one we spoke about calcium

and phosphate as ions in bone right except they're dissolved inside of that bone and they form hydroxyapetite they form make the bone hard but here calcium and phosphate are important when it comes to signaling muscle contraction neurons firing off same with when it comes to sodium and pottassium they all play individual and separate roles hydrogen ions are about pH maintaining the pH how acidic and basic the environment is so they are present and dissolved within our blood specifically the plasma what nutrients are we referring to here mainly referring to things like glucose and amino acids

now you might be thinking but we also have fatty acids part of triglycerides but it's fat and generally the fat and fatty acids like to travel through the lymphatic system however after a big meal this plasma can get a little bit cloudy because you do have fatty acids floating around but generally they're bound up to something that certain carrier molecules so uh like highdensity lipop proteins for example so they're the nutrients waste what type of wastes do we have so I'll just put an arrow there what type of wastes do we have mainly things like

Ura and creatinin just to name a couple but there's also like uric acid they're metabolic byproducts right so of protein metabolism when we take Nitro remember amino acids right that's part of proteins amine means there's a nitrogen group and we need to get rid of that nitrogen group and we do that via Ura creatinin is a byproduct of muscle metabolism so creatine is required to hand phosphates back to ATP that's lost the phosphate so basically hands them to ADP and part of this um metabolic process a byproduct is creatinin now interesting thing here is they're

both generally produced and excreted um at a normal regular amount so we can measure them and if they're abundant or if they're too high or too low can give us an indication as to what might be happening in the body hormones well there's a multitude of hormones and generally water soluble hormones but I said that fat soluble hormones can also travel with elbin for example so there's many hormones that travel through the bloodstream and the gases are mostly oxygen and carbon dioxide so these gases can be directly dissolved in the water of the blood plasma

or they can be carried which we'll talk about shortly all right so that's the blood plasma let's now talk about this next layer here the smallest layer which its name is called The Buffy coat what a weird name Buffy coat now the Buffy coat is this sort of whitish frothy layer and it makes up around about 1% of total blood volume what is inside of this Buffy coat let's take a look well inside of this Buffy coat we have two major things first thing we have are lucaites lucaites we also know lucaites as white blood

cells white blood cells what are our white blood cells well a way I like to remember our White blood cells is the pneumonic never let monkeys eat bananas wonderful there's that pneumonic and as we know what a pneumonics do you take the first letter from each of these and it tells you what it is so n is neutrophils we got neutrophils here L is lymphocytes lymphocytes m is monocytes e is eosinophils and B is basophils so that's a great pneumonic to remember and it also tells you about their quantity from highest to lowest so neutrophils

are the most abundant white blood cells and basophils are the least abundant white blood cells what a great way to remember these all right just very quickly what do they do all right white blood cells part of the immune system they help protect us so there's an important protection role here neutrophils are usually when it comes to an infection or some sort of damage to tissue bacterial viral whatever it may be neutrophils are usually the first to the site and they're the first to die and they form pus when you see pus mostly dead neutrophils

they go in to help neutralize and also get rid of clean up that area lymphocytes there's two major types which we know are te- cells and B cells and there's subcategories of each so we know there's t- helper cells and cytotoxic tea cells and B cells can turn into plasma cells which make those antibodies which we spoke about before they're very important when it comes to our adaptive immune system so they can develop a memory an immunological memory if they're exposed to a pathogen or an antigen they can remember it monos sites monocytes turn into

macres once they're in the tissue so macras is a big ERS so monocytes in the blood sort of just wander around until they've been called upon by the neutrophils and the infected site and they move out of the blood vessel and once they're in the tissue they turn to macrofagos gobble things up monoc sites can also seed particular tissues and become dendritic cells very similar to macrophases then we've got eosinophils and basophils a lot of overlap here they're both important for allergic response and eosinophils well and basophils but uh important with parasitic helping fight parasitic

infections so there are our white blood cells when we have a look at the white blood cells in our whole blood you'll find that we have around about 5,000 to 10,000 per micr L microl ler not Mill microl ler so that's 1,000th of a milliliter we've got 5,000 to 1,000 lucites present now the other thing in the coat are thrombocytes thrombocytes now the other name we know thrombocytes as are platelets now we know platelets are really important when it comes to clotting and therefore they work intimately with fibrinogen and specifically fibron again watch that hemostasis

or clotting Cascade video for more details so so platelets are important they're fragments of cells right so platelets aren't entire cells they're fragments of cells they actually come from one cell type called a mega caros site which what it does really interestingly it's made in the bone marrow it becomes really big and it blbs out like puts an arm through the sinos soidal capillaries into the bloodstream and then basically chop chop chop chop chop chop chop chop chops this arm off and those little chopped up pieces become platelets crazy so how many platelets do we

have per micr ler if we're looking like we did with the thrombocytes it's going to be around about 200 to 400,000 per micr it's a lot right and again their job is clotting finally we're up to this last area here so this last part is pretty much just compact red blood cells and generally speaking so let's write this down first compact red blood cells let's call them by their names arthr sites which we know as rbc's now this is important because there's a a thing called hematocrite now measuring hematocrite is simply measuring the percentage of

whole blood that's made up of arthrits how do you do that well you get a ruler you go you measure the length of that and find out the length of that and you divide them generally speaking arith aryes should make up around about 45% of your total blood volume but it can be different between males and females so for example so again let's write this down the term is hematocrit so measuring hematocrit is measuring the compact aryes hemato crit and for males generally speaking it's going to be 47% plus or minus 5% and for females

it can be 42% plus or minus 5% all right so there's obviously a buffering capacity there what's the whole point of these uh of doing a hematocrite and finding out the red blood cell percentage well red blood cells are really important because they carry the gases within our body right so the RBC are carrying oxygen and carbon dioxide oxygen to the tissues to make to produce ATP and getting rid of the waste product which is carbon dioxide and sending it to the lungs that's super important without this process we die very quickly and so we

produce huge amounts of red blood cells so comparing it to these two red blood cells we have around about 5 million per microliter so an enormous amount 5 million red blood cells per micr leader and they excuse me they're just filled with hemoglobin just filled with it so if we were to have a look at a red blood cell let's maybe draw it up here right have a look at a red blood cell what You' find that it's around about if you look at the length of it it's around about 8 micrometers and its thickest

area is around about 2 micrometers extremely flexible can fold in upon itself it's eight micrometers so what happens is when you get to the smallest capillaries of the body it's only wide enough to fit red blood cells through single file one at a time right and the great thing is they've got the capacity to fold in upon themselves they are filled with hemoglobin hemoglobin carries the oxygen and the carbon dioxide I told you that oxygen and carbon dioxide can be dissolved directly in the plasma and that's true but the vast majority are going to be

bound to either the heem portion if it's oxygen or the globin portion if it's carbon dioxide so they're filled with hemoglobin there's no organel there's no nucleus nothing so they don't have the capacity to create new proteins and regenerate so their lifespan is only around about 120 days so how do we know when it's time for them to go well as they get older their shape starts to deform they're less likely to be flexible foldable and all those types of things and so as the blood moves through all the different tissues of the body it's

going to get to places like the spleen and the liver where they have like a mesh work and healthy red blood cells fit through no problem but unhealthy old red blood cells get caught up and there like the spleen for example which is the elephant graveyard for red blood cells they're now targeted for Destruction and that means they pull it apart they take the ion that's inside and they recycle it they take the globin which are amino acids and recycle those amino acids and then they take the heem and they undergo multiple processes of breaking

that heem down think about Billy Ruben for example and you can poo and pee that out and that gives you the color of your urine which is that either yellowy color or the color of your poo which is the brown color so that is the red blood cell carries the oxygen and carbon dioxide remember that when we look at the red blood cell which carries the oxygen carbon dioxide it's filled with I said hemoglobin now hemoglobin is made up of four globin uh molecules you've got two alpha I'm going to draw like that and then

two beta which I'm going to draw like that that this for this here is hemoglobin right so this here is if I can spell it hemoglobin now the thing is embedded inside of each of these is he so these are just the globin these are just the amino acids the proteins right but inside you got this circular he present right so now we've got the heem and what the heem has as like the crown jewels right in the middle is an ion ion an ion ion ion ion so that there is the ion ion which

is Fe 2+ so there's four of them so one hemoglobin molecule has four ion ions here's the thing one red blood cell has 250 million hemoglobin each has four ion ions so multiply that by four that means you have the and this is the thing the oxygen binds to the ion ion so one hemoglobin can bind four oxygen so 250 million hemoglobin Time 4 right because you can bind four oxygen to it 1 billion 1 billion 1 billion oxygen molecules combin two in a single red blood cell and we have 5 million red blood cells

per microliter so this is a summary and an overview of an introduction to blood hi everyone Dr Mike here if you enjoyed this video please hit like And subscribe we've got hundreds of others just like this if you want to contact us please do so on social media we are on Instagram Twitter and Tik Tok at Dr Mike todorovich at d r m i k e t o d o r o v i c speak to you [Music] soon