continuing with our discussion of the blood quick review bloods divided up into two components and the plasma and the formed elements the formed elements being the actual living cells the plasma being the matrix of the blood the matrix is further broken down into the fluid portion which is the what's also called the ground substance which is primarily the water and then the protein portions the plasma proteins so we finished talking about the different plasma proteins albumin being the main one responsible for osmotic pressure the globulin is being the antibodies primarily the fibrinogen being the fluid portion that is converted into a solid for support protein called fibrin so we can clot the blood and then finally the regulatory proteins which of course have things like enzyme G pro enzymes we know these are necessary for the chemical reactions to take place in the body and then the hormones that are actually protein-based hormones because some hormones are not protein-based hormones such as the steroid hormones they are actually lipid based hormones so we do definitely find hormones in the blood because they're being transported to different parts of the body to you know do whatever they do which we will talk about that when we get to the endocrine system now this last category here only makes up 1% of the plasma but it's really the whole purpose for having blood in other words what is blood are almost the purpose what is blood carrying to the body well it's actually carrying and making sure our electrolytes these ions that are so important to what's going on in the body for all the physiological responses that the body makes the you know they're not necessarily a huge proportion of the blood but they're an extremely huge important portion of what the blood is doing for us so you know anytime you do a physiology you're going to be seeing these things now the next thing is why do we eat so we can take the organic nutrient to ourselves so even though at any one time is still a relatively small amount of what's in our blood obviously we can't exist very long without these things so our carbohydrates our you know proteins burned out to our amino acids our lipids triglycerides you know fatty acids cholesterol all those things are actually you know gonna be used by the cells so our blood is going to carry it there and then finally we're carrying nutrients to the cells butter cells are going to produce wastes and some of those wastes are gonna be you know filtered in the blood through the kidneys to get rid of from the body other parts of those wastes are going to be made from some of the actual breakdown of some of the formed elements like our bilirubin and so forth but we're gonna primarily be trying to get rid of the urea and uric acid creatinine and some of the ammonium ions and also help in balancing some of these ions here so so again bottom line is our blood carries the stuff to ourselves and needs it get step away from the cells in other parts of the body so it doesn't build up a toxicity so obviously partners work kidneys come in they're going to be filtering most of this out so again this is primarily that breakdown of what's happening in the plasma one of the major components of the blood but what about the formed elements what is it made up of well it's made up of actual living cells when we look at this we see that the living cells called formed elements are broken down into basically three categories the red blood cells called erythrocytes the white blood cells off also called leukocytes and the platelets now that the platelets and the leukocytes by far are very very small category compared to the red blood cells I have seen other numbers that were quite as high as as the 99.9% so there that may be a little bit debatable according to whose information you're reading in one context it is but the bottom line for what to understand is it's in the high extreme high 90s of our of our cells in her blood what that's called our hematocrit being our red blood cells okay so so the white blood cells course the red blood cells we know their main job is to carry oxygen even though they also can carry some carbon dioxide well you're talking about that when we get the respiratory system later and talked about how gases are dissolved and you know what how they how they're carried in our blood but but for right now we know the main job of red blood cell is to carry oxygen each red blood cell house if it were a hundred percent saturated which usually it's only up to about 98 plus percent saturated but if it were a hundred percent saturated it could actually hold a billion molecules of oxygen so one red blood cell a billion on molecules of oxygen and we have more red blood cells in the other cells so that that goes a long ways now the white blood cells and there are different types of white blood cells these are subcategories of our leukocytes or white blood cells and then even the lymphocytes themselves also have subcategories that we're going to be talking about and talking about some detail when we get into the into immunity right now though let's look at the red blood cells and talk about some of the things that make them so special now looking at this picture and at all these pictures actually we you know the majority of cells in this picture are red blood cells notice how they're kind of lighter in the middle and darker on the ends and you can see the ends are actually we say this is a biconcave disk shape meaning that there's kind of you know it's kind of like a breath mint or something and this actually helps a couple different things one thing it helps increase the surface area if the thickness were only the what the thickness is in the middle all the way through we wouldn't have near as much surface area if the thickness were the same thickness of the of the edges of it though we would have we wouldn't have very much flexibility so we get some flexibility by having a thinner middle and a thicker outer area and if flexibility is important because as you can see in this picture here we see a bunch of red blood cells kind of stacked on each other moving through a capillary sometimes the capillaries are actually a little smaller than the red blood cells so they have to be able to bend to actually get through back through the capillaries so that flexibility is really important for a red blood cell to be able to circulate properly let the surface area is also important to make sure that we can carry enough oxygen you know with the number of red blood cells that we have looking at our notes here and you go back and read them but I'm going to point out a couple of highlights from this is that you know that one of the main jobs of our red blood cell of course is to transport oxygen and it does this by containing a protein called hemoglobin that binds loosely with oxygen and then part of the hemoglobin actually binds loosely with carbon dioxide now it doesn't bind with oxygen carbon dioxide you know at the same place and usually not at the same time but it does bind to both of them but it does bind do more oxygen than it does carbon dioxide but it's important that it binds loosely to it because if it picks it up we also want it to be able to give it up to the areas of the body that need that oxygen and not hold on to it okay now the red blood cells actually the most numerous cell in the body whereas more red blood cells than any other type of cell and again it it's to distinguish it from other cells we know that all cells start out with a membrane surrounding them a nucleus in them and then the cytoplasm with the organelles but the red blood cell is a little bit different in that it actually loses that nucleus when it actually starts developing its its hemoglobin so it does start out with a red with a nucleus but by the time universal bloodstream it's lost its nucleus okay we'll talk we'll look at that a little bit later now again we've mentioned their flexibility because they have to squeeze through capillaries another thing that you know red blood cells the statement distinguishes them from other cells is that when it starts forming all of this hemoglobin and by the way there is a there is a hormone called erythropoietin which is actually released from your kidneys that triggers this to actually build all that hemoglobin then it actually starts to crowding out some of those cytoplasmic organelles where by the time it's mature it's it's about 95 percent hemoglobin and just a few other little things so it doesn't really have mitochondria because it doesn't want that mitochondria to actually use up the oxygen that it's trying to actually deliver to other parts of the body it still goes through you know some cellular respiration as far as it goes through glycolysis but so it only makes a small amount of the ATP that other cells may make that have mitochondria but again the you know it's all about the specialization of doing its job of delivering oxygen not using oxygen okay now another kind of interesting thing and an important thing about the red blood cell is because it forms all this hemoglobin now in the stem cell in its life cycle is the stem so I didn't have the hemoglobin it got exposed to the hormone that triggered transcription of translation of the hemoglobin and then when I started making so much hemoglobin then it started crowding out the organelles so one thing the good thing about that we've got a lot of hemoglobin we can carry a lot of oxygen the bad thing about that though is that since it circulates through the body about once a minute or so then after about a hundred 20 days of traveling about 700 miles it's gonna actually become squeezing through those capillaries it's going to it's going to become you know it's gonna become damaged and therefore we're gonna have to replace it about every 120 days so you can see this little diagram here where our red blood cells are all being made in our bone marrow so that's one of the important points of bone for specific parts of the marrow and different bones that is where our blood cells our red blood cells are primarily being formed and we'll look at that formation a little bit closer in a minute but when they are formed it goes into circulation then there's about a 120 day average lifespan and so again because during this time got rid of it's during the formation time it got rid of the organelles and you know basically it's just a big packet of hemoglobin you know still a living cell but it's mainly a packet for 95% the proteins are hemoglobin so it does very little else it can't really repair itself so as it circulates through the body through the capillaries it's going to start being damaged and eventually that's going to get to a point where either in the spleen or liver or the bone marrow themselves they're gonna be white blood cells called macrophages and they're gonna detect the damage now if they come across a red blood cell it's not damaged they're not going to do anything to it but if they come across a red blood cell that's been damaged they're going to phagocytize it engulf it they're going to break it down and they're basically going to recycle much of what they broke down to build new red blood cells and then the other the other parts of what they're breaking down especially the heme group and they're going to convert it to building burden and bilirubin and then the Billy Rubin is actually going to be sent to the liver where it's going to be turned into bile and bile helps us emulsify our fat contents and then some of it will also be gotten rid of with our kidneys eliminated from our kidneys and then that bile of course after it does its job will be eliminated from our large intestine as species now let's let's look at this formation here okay there's different terminology according to the stages but notice where we're at we're in the bone marrow where our red blood cells are at the stem cell level where they are being turned into the mature red blood cell so they can enter into our circulation so notice here without worried about necessarily the terminology that's used though notice what's happening is here we have a nucleus here we don't have a nucleus and reason why is because when this goes through this process and it is it starts making a bunch of hemoglobin it ejects the nucleus it gets so crowded it actually at Jackson nucleus along with the other organelles are the majority of the other organelles and so what my atomic enters into the bloodstream that it's their phospholipid bilayer membrane and the by contact disk shape and 95% of the proteins inside which remember that's mainly what our cells are or proteins is hemoglobin okay so looking at our hemoglobin right here notice here is one hemoglobin molecule and there are on the average about 250 million hemoglobin molecules in one red blood cell now notice that in the same of lipid molecule it's actually a quaternary protein made it but for tertiary units and here each unit has a heme group that is one two three four one heme group if we look at the the chemistry of it we see that in the middle is iron it's the iron that loosely bonds with the oxygen it's important to remember that it loosely bonds with that oxygen so it can give it up once it gets to an area with low oxygen concentrations so it will easily give it up easily except and easily give up that oxygen which is the purpose of the hemoglobin