today we are going to talk about body fluid compartments right body fluid compartments and body fluids are very important not only in physiology but also when you are managing your patients in the medical floors or when you are managing your patients on the surgical floor right you must know that what are the normal types of fluids present in different body fluid compartments and in different diseases how the body fluid compartments are altered and how you can restore the balance of normal body fluid compartments right so let's start with the very basic first of all you must know that the most abundant substance present in our body is water we are made with lot of water thank God it's organized in proper biological way right about 60 percent of our body weight is water right so let me tell you how body how the water is distributed in different compartments in the body first of all all of you know that we are having lot of cells we are made of cells right so let's put the food cells here right now because this is yourself and here is suppose your circulatory system circulatory system in which blood is circulating right now of course all the reactions in the cells many of the reactions they are going on in aqueous environment so this is the amount of water which is present within the cells right this blue color is indicating the amount of water which is present intra cellularly is that right now all the water which is present within the cells right all the water which is present in within all the cells of the body put together this is called intracellular fluid so what is this fluid called yes please enter cellular fluid what is intracellular fluid intracellular intracellular fluid compartment is the fluid compartment of the body right consisting of all the water present within the cell right then around the cells there is water also water is present around the cell as well right in a way cell the bathing in water they are surrounded by water now this green color is showing the water which is outside the cells and surrounding the cells right now this green color of the water is outside the cells so we can call it extracellular water now this extra solar water which is present around the cells right this is not circulating so this is the non-circulatory non-circulating part of extracellular water then of course water is also present in the plasma of course blood has rbcs it has red blood cells white blood cells and platelets I'm just showing red blood cells but this is what is this plasma of course it's water also right major component of the plasma is water plasma is having lot of substances but most abundant component is water now how many water compartments are there first of all intracellular fluid then this green and this red both of them are extracellular they are outside the cell remember the water which is present within the rbcs within the red blood cell this is intracellular this water is intracellular so in the blood within the cells red blood cells white blood cells and platelets is intracellular but because blood cells are floating and circulating within the plasma right present along with the plasma and the all the water in the plasma is considered extra cellular right I think if I'm really intelligent so I should make this also which color green yeah I have some intelligent students so plasma should be made even though it's not green but just to make the concept more visually clear to your semi-intelligent or intelligent mind I must say right so what we can see really here I think RBC is leaking it's very bad okay now what we see that blue is the intracellular fluid compartment and this green component around the cell and this green color are present within the vascular system but outside the blood cells this is plasma now plasma and this fluid both of them are extracellular both of them are extra cellular right out of these extra cellular fluids this fluid which especially present around the cells this component right this component this fluid is that part of the extracellular fluid which is not circulating and plasma is that part of the extracellular fluid which is circulated is that right so extracellular fluid is two type non-circulating fluid we surrounds the South and circulating extracellular fluid which is present in the vascular system and lymphatic system right now this non-circulating this non-circulating extracellular fluid which is surrounding the cells is called interstitial fluid what is it interstitial fluid and of course no fun in telling you people what is this yes what is this plasma plasma interstitial fluid and intra cellular fluid right in another way now let's make a very simplified diagram of the whole this situation if we make a simplified diagram let's put all the cells together if you put all the cells together and in this diagram we make a very big cell all cells put together and now yeah this diagram is representative of which fluid intracellular fluid this diagram is representative of intracellular fluid then outside it this is intracellular fluid of all body and now we can make you remember that communication the communication between the plasma and the interstitial fluid is the capillary wall and you must know that capillary walls are very very porous they allow the exchange of fluid and some other substances capillary walls through the capillary walls fluid in the plasma and interstitial fluid they are exchanged with each other is that right the real difference in plasma and the interstitial fluid is one difference I told you plasma is circulating interstitial fluid is not circulating plasma is present within the vascular system into special fluid is present around the cells plasma has lot of proteins interstitial fluid does not have that much protein conceptually speaking interstitial fluid is ultra filtrate of plasma that if you filter the plasma under pressure but don't allow the proteins to filter out then whatever will come out is interstitial fluid so interstitial fluid composition is very similar to plasma but minus plasma proteins and plasma protein associate bound substances because any substance which is bound with the plasma protein will not easily filter out here is that right so anyway now this is all intracellular fluid and this component is representing extracellular fluid and this extra cellular fluid has this component what is this enter fluid right and what is here I'm not showing rbcs but what is this plasma fluid is that right what is this plasma fluid right so in this way here we can make a diagram that you understand from where this diagram came it's clear to all of you one thing is very important primarily body fluids are divided into intracellular fluid and extracellular fluid right so let me tell you that if we put all the total body water all the total body water so we say that let's suppose I put your total body weight first total body weight out of the total body weight how much is the total body water yes it's approximately 60 percent and 40 percent is your dry weight right so what really happens the total body water is about 60 percent of your total weight is that right of course total body water will include intracellular fluid as well as extracellular fluid all body water right but you have to remember one thing young females have less water Yeah Austin does not agree to me why you don't agree I know there are reasons you don't agree but still they are having less water than you why young females have less water Carlos anyone yeah he's saying something in his heart I cannot understand anyone wise enough or intelligent enough boys should know the answer they are so much interested in young females anyone knows why they have less water actually boys are perplexed it's against their basic ideas look the reason is that adipose tissue fat tissue it has less water look if I draw a fat cell fat cell has a big fat droplet it's a lipid droplet and there's very little water into it are you understanding females have more fat or males have generally speaking or even though some of these male can beat the females in this matter but still generally speaking females have more fat or adipose tissue or males have males have more adipose tissue what kind of females you have been coming across females have more adipose tissue I must write it down in your book If You Don't Know by a simple observation because females have more adipose tissue when in adipose tissue there is less water so females and obese male even they have less water for example a young female little bit of bees she has 50 percent of body weight as water but if you come across a male male as you're really having less adipose tissue and male who is thin bony and skinny not much adipose tissue he may have 70 percent of the water I'm talking about which water total body water is that right so remember that even though on average we say that in human beings 60 percent of the body weight is water but it varies from person to person right people who are males and especially thin less Edibles they are having lesser depose tissue they are having more water and females and especially who are obese they are having less water so let's go with General concept that uh standard person I don't know what is meant by the standard person but a standard person a model person will have about 60 percent of total body water out of this 60 percent right let me put it here that all this is total total body water right this consists of from here all of this is total body water that include about 60 percent now total body water is primarily divided into two compartment intracellular fluid and extracellular fluid right so we can say the total body water is divided into yes intra cellular fluid compartment and extracellular fluid compartment intracellular and extracellular fluid compartment right now you see intracellular compartment is larger right out of this total 60 percent two third is intracellular and one third is extracellular it means 40 percent is out of the sixty percent out of the total lesson how much weight you have let's suppose you have 100 kg it's an unusual weight but anyway suppose you are having 100 kg then how much water you have 60 I think later not kg letters right out of the 60 liter 40 liter will be intracellular fluid and 20 liter will be yes 20 letter is extrasala fluid is that right now it's 20 percent as well now out of this you again divide extra cellular fluid into two areas what are the two areas extracellular fluid yes what is this enter fluid and plasma right interstitial fluid that makes about out of extracellular fluid interstitial fluid is three fourth and plasma is about one-fourth of that is that right no problem up to this right having said all of this now I will talk about little bit about the composition of the different fluid compartment important cations that is positively charged substances and anions in different compartment now the most important cations within the cells intracellularly are yes please potassium and magnesium not sodium sodium is not the major intracellular cations remember cells are just the bags of potassium floating into extracellular fluid which is the ocean of sodium you must remember you remember by evolution you have heard of word Evolution evolution yes according to Darwin or Evolution Concepts life started from ocean life started from Ocean so when life started with simple molecules and then eventually converted into cell and then it came to the land is that right when life came to the land basically all metabolic activities and survival of the cell was designed to survive well in the ocean environment and you know ocean fluid is very rich in sodium and chloride all of you must have tasted ocean and tears right so what happens that because life started in the ocean and primitive cells very early cells our great great ancestors right they were well designed biologically to be active and survive in the sodium Rich ocean water when they came to the surface they brought the ocean water with them you know our extracellular fluid is very rich sodium and chloride it is just like a small ocean environment surrounding everything look at the intelligence of the system right that when cell came to the land and then many cells further evolved and multicellular organism come one of this organism is Carlos now Carlos has so many cells but every cell is still having extracellular fluid around it which is very rich and sodium and chloride so whenever we talk about sodium chloride we must remember it is the major solute solute in extracellular fluid not intracellular fluid am I clear so Zelda region not in sodium and chloride they are rich in potassium and magnesium as their cations and major anions in the cells are yes in the South what are the major negatively charred proteins intracellular proteins they are negatively charged even plasma proteins are also negatively charged at physiological pH Plus in the cells the very important organic compounds what are organic compounds yes what are organic compounds please tell me ATP adenosine triphosphate yes we also call it these organic compound which are having phosphate we call it organic phosphates okay for your easiness I put it here organic phosphates what are the intracellular organic phosphates adenosine triphosphate adenosine diphosphate adenosine monophosphate right and of course phosphates are positively charged and negatively charged negatively charged so within the cell the major positive charges are present on potassium and magnesium measure negative charges are present in organic phosphates like ATP ADP and amp and of course on proteins so we can say intracellular fluid is a soup of potassium magnesium with lot of organic phosphates and proteins is that right and of course there's no fun in memorizing it that this cell should be surrounded by extracellular fluid which is rich in sodium and chloride right so I will put here which is the major catine here sodium either the sodium is complex with chloride mostly or to some degree to bicarb sodium and chloride and what is the major anion here again it is sodium sorry cation the sodium and negative charges here are mainly by the chloride and bicarb but you have to remember there are lot more proteins present in what is this plasma they are also negatively charged right so what we really see that intracellular fluid has potassium and magnesium as major cata cations and organic phosphates and intracellular proteins as major anions and an extracellular fluid sodium chloride and sodium bicarb they are making major solutes sodium being cation chloride and bicarb as exosola anions and in the plasma there are also plasma proteins which are negatively charged one thing which you should remember that biological partition between the plasma and the interstitial fluid is capillary membrane and capillary membrane is very permeable and it does not offer any barrier to the movement of sodium and chloride listen carefully it's very very important sodium and chloride right is separated from plasma and interstitial fluid by capillary membrane but capillary membrane does not offer any resistance to the movement of sodium and chloride it's highly porous what does it mean that sodium chloride concentration will be always equal almost equal in plasma and into social fluid because sodium chloride freely equilibried is that right but you have to remember here the partition is what is this partition yes please cell membrane cell membrane does not allow the sodium chloride to move freely look the sodium want to go in but it will cannot enter in coming bouncing back this is very important concept you are understanding why it is so important yes why it is so important to know it it's a very important concept Dr najib gets mad over this concept that sodium is Major extra cellular solute along with the chloride and bicarb and it does not freely move in and out of the cell an extracellular fluid why it is so important to know anyone we are all doctors all our life we will be giving the sodium and chloride to the what is this patients normal saline and many diseases will lose sodium and chloride why this concept is so important it's a very basic thing my friends attention please before you tell me something funny listen if sodium cannot look sodium cannot move in and out between extracellular fluid and Interstellar fluid and as I told you but sodium can freely equilibrate between what is this interstitial and blood now listen just put a simple concept the amount of water present in any compartment is proportionate to the number of osmotically active particle you know fluid always follow the fluid always follow the solutes you don't know this time you don't understand fluid in the compartments wherever you put the more solute fluid will love to be with solutes is that right now imagine I put lot of sodium chloride here suppose I put a intravenous infusion or lot of sodium chloride very heavy concentration of sodium chloride or I gift you a potato potato chips bag you know potato chips you must keep on eating so potato chips bag you should eat a lot they have lot of salt so lot of salt will go here from git so salt is added to extracellular fluid now it's lot of sodium chloride come here I put a lot of sodium chloride in extracellular compartment can sodium chloride enter into cells no when sodium chloride cannot enter into the cell it will concentrate outside outside in extra cellular environment osmotically active particles will be less or more when I have put more sodium chloride here osmotically active particles will be less or more more so it will become hyper or smaller if if I put lar I give you lot of sodium chloride tablets to eat you or if I'm good to you I give you salty potato chips a lot of sodium will come here problem is that from git potato chips sodium will go into blood and exercise fluid but it cannot enter into cells so blood will become less salty or more salty more salty isn't it hyper or smaller when it will become hyper or smaller should solute concentration in extra solar compartment will go up as compared to the solute concentration in intracellular compartment what will happen now solute drag the water if sodium chloride cannot go here the sodium chloride will increase the osmotic pressure here and water will be sucked from intracellular compartment to the extra solo compartment why because when you are adding solutes here right first lesson before adding the sodium chloride in a normal healthy person even though here is sodium sodium and chlorides and sodium bicarbonate major solutes and here is potassium magnesium and protein then these are organic phosphate are major solute but in a healthy person intracellular osmolarity an extracellular osmolarity are absolutely equal in a healthy person in equilibrium state number of osmotically active particles in extracellular fluid and number of osmotically active particles in intracellular fluid are absolutely equal even though type of the solute is different but number of solute particles which are osmotically active normally extracellularly and intracellularly are different and both of them are holding their water faithful to them but when you add sodium chloride here by potato chips or by eating lot of sodium chloride tablets this area become hyper or smaller its osmolality become more than the normal osmolarity when the osmolarity in this area become more than the normal osmolarity you know what is the normal osmolarity first of all anyone look if we put all the solute solutes osmotic osmolarity together it is about to be very exact it is to 90 Milli or small per liter let me tell you what is meant by this if you take one liter of extracellular fluid if you take one liter of extra solar fluid then all the K times and anions together which are present here all the cation then anions together they produce osmotic power the power to hold the water is about 290 Milli or small per liter right of course main contribution is done in excess of fluid by sodium and chloride but there are other cations and anions in smaller amount is calcium magnesium there are many other so all of the osmotically active particles present in extracellular fluid right their osmotic power the power to hold the water put together is how much 290 Milli or small per liter but in most of the books we make a round figure and we say it normal is about 300 Milli or small per liter but this is to be very exact I should want extremely is that it is 287 but don't be like that just remember that 300 is 300 Milli or small this is the osmolarity of extracellular fluid remember if you have pure water pure water what is the osmolarity what is the osmolarity of pure water yes zero oh my friends I need to really teach properly I should not get lazy as a teacher look this is a water container and here I put up yes yes yes in this water container I put here semi-permeable membrane right look this is a membrane and on both sides there is water there is water here and there is water here this is compartment a this is compartment B now listen carefully if both compartment have pure water water water is allowed to move through this membrane so water will equally move on both side and water level on both side will be equal now you do something clever you start adding sodium chloride here what are these particles sodium chloride what will happen solute pull the fluid or we can say this area will develop osmolarity now a compartmental will have more osmolarity than the compartment what is osmolarity osmolarity is determined by the number of the osmotically active particles in a fluid is that right now listen attention plays the two ways to explain this situation one situation is this is hyperosmolar fluid in a compartment B compartment is less or smaller so water will move from which direction to which direction from B to a water will move from B to a one there are two ways to explain it one way to explain this phenomenon is that because a has more solute and solute can attract the particles is that right when we put the solute particles into a container this membrane does not allow the solute to move in this direction ideally solute should move and it should go to both directions but because this membrane does not allow what it does not allow the movement of solute okay let me make it easy solutes are like beautiful young girls and water is like boys you know water follows now what happens if you add lot of young girls here and no girl is allowed to come here what will happen to boys here they will start moving in that direction is it difficult to understand it's so simple common experience so when you add girls or solute here they develop osmotic pressure right and what really happens that solute attract water solute is not allowed to go to B compartment but water is allowed to move from B to a so water will start moving in that direction so after some time you will find that water level here has become less and water level there has gone up is that right so you just drag the water this is one way to explain another way to explain is that when you put the solute here then water concentration on this side become less and water concentration on this side is high because before putting the solute water molecule concentration in B compartment and a compartment was equal but when you add solute here then water become less concentrated on this side and it is remains well concentrated on this side and everyone knows if molecules are allowed to move they move from high concentration to lower concentration so actually water will move from higher concentration to low concentration this is two ways to explain one way is that water moves every substance every molecule which is allowed to move will move from high concentration to low concentration right not only solute even solvent also even solvent solvent is water now again when put more sodium chloride here we make this area hyper or smaller because solutes are more or we make this water less concentrated so water from high concentration will move to low concentration this is one explanation other explanation is simple concept that whenever there are more solute in one side of the container and if solutes are not allowed to equilibrate then area which is having more solute and which is hyper smaller will drag the water to that side am I clear now listen what is the concept of osmotic pressure from where the pressure comes into this let me tell you you added solute here water is now coming to this and trying to raise the pressure in this compartment you know when more water is coming here right what you do you put a piston here you know pressure device now the amount of pressure which you are supposed to apply to prevent the movement of water is called osmotic pressure because listen again carefully what did we do initially there were pure water on both sides no move neck movement right we added solute here it become hyper or smaller water started moving from B to a if we want to prevent the movement of water from B to a we have to apply some pressure in the a compartment that pressure is the amount of pressure required to prevent the movement of water from high pose molar to hyper or smaller fluid that pressure is equal to the pressure with which water is trying to move that pressure is called osmotic pressure that pressure was originally generated by this solute particles that was called osmotic pressure so when water was moving from B to a compartment what is that what is moving under the influence of osmotic pressure of hyper osmolar fluid in a compartment now listen carefully if we keep on adding more and more salt here if you keep on adding more and more salt here a solution will keep on getting more and more hyper or smaller and fluid from B will keep on moving on the a side now let's suppose we remove this we have added sodium chloride water has gone there here water level has gone up now we do another try we add another solute here but osmotically look osmotically active particle now in the B area is equal to the area what will happen now water will start coming back until both sides become equal you are intelligent only you don't tell people right now you see under these circumstances what will happen water on both sides will come equal now imagine in any side you add more osmotically active particles water will start moving in that direction is that right suppose this is another solute if I add this solute more to this side water will move to that side but rather than a compartment the same particle that move on this side and become hyper a smaller whatever move in this direction are you understanding so water is like boys follows the girls or we can say that water in different compartment if right will follow what solutes is that right those solutes which cannot move across the membrane am I right now come back to this diagram because this is going to be our Master diagram we were talking about potato chips don't forget them you have eaten a lot of potato chips lot of sodium chloride is added to the here now sodium chloride can freely move in between plasma and interstitial fluid so whatever added added sodium chloride is there that will be equally equilibried in these two compartment what is that plasma compartment and interstitial compartment so we can say by eating potato chips we have added more salt in extracellular fluid but this salt added salt when I try to go into cell can it go no so newly added sodium chloride is added to this compartment now this compartment will have what higher osmolarity when you eat lot of potato chips which are very salty or you take lot of sodium chloride tablets actually you are adding lot of sodium chloride molecule the solute particles into extra solar fluid and extracellular fluid become hyper or smaller so smallity will become more than 300. now when it become hyper or smaller water concentration is more here and less here or solute are here to drag the water and water can move through the membrane so what will happen boys will start escaping to there so intracellular compartment will start shrinking not boys I think water so what will happen intracellular water will start moving towards extrasolar compartment cells will start shrinking intracellular compartment will start shrinking and extra vascular compartment of extracellular intracellular compartment will start shrinking an extra cellular compartment will start spending there will be extra cellular fluid compartment expansion are you understanding me and fluid will keep on moving Keep On Moving until osmolarity on both sides again become equal how when this water will keep on moving from here to here it will start getting dilute and this will start getting concentrated originally before giving the sodium chloride osmolarity here was 300 and it was also 300 when you added the sodium here it become three 20. then what will start moving there water when water will be coming here it will get little bit diluted and it will become 310. and it will get little bit concentrated it will also become 310 at 3 10 when osmolarity will become equal on both sides net movement of water will stop so what has happened that water shift has been there to equalize the extra solar fluid osmolarity and intracellular fluid osmolarity am I clear no problem into this let's do another experiment forget about this let's suppose now you people have to tell me let's suppose should I remove all these things so that you can see it more clearly at least this funny okay I will make it more clear and of course you should not forget a part of it is accessible fluid is divided into plasma and interstitial fluid and there's no fun in telling you again that this is rich in sodium and chloride and bicarb is that right all of this and this is written yes hurry up potassium magnesium and yes organic phosphates organic phosphates and proteins right proteins are also present here previous experiment was we were added the sodium chloride here made it hyper or smaller water shifted from intracellular compartment to accessible compartment intracellular compartment Al compartment expand until osmolarity of intracellular and extracellular compartment again becomes equal it achieves a steady state now do another thing again to Baseline is what is the osmolarity here 300 and what is here 300 now you do a trick let us suppose you are suffering from a disease or some condition in which water is lost from here less solute are lost and more water is lost for example when you have high grade fever when you are having fever water is evaporating from respiratory system and also from the skin water is living so this water during fever when water is evaporating do you think salt sodium chloride is also vibrating no do you think tablets or sodium chloride will go out of the body no so water is evaporating during fever high grade prolonged fever what is happening that this compartment is shrinking is that right extra cellular compartment is shrinking and it's solute will remain the same but amount of water will come less so it will become concentrated so its osmolality will become 320 this is another situation I'm telling you what is being lost from here water when water is being lost from here it becomes what highly concentrated osmolarity here increases again what will happen this hyperosmolar extra solar fluid which has lost the water more water and less solute resource molality is more than the osmolarity of fluid and what will happen again water will start shifting again so it will keep on shifting until it becomes little bit diluted and it becomes little bit concentrated until due to arrival of the water it dropped to from 320 to 310 and it become concentrated it also becomes 310 a new steady state is achieved am I right another experiment let's suppose we have a bet with Carlos I say Carlos I will give you him one dollar if you take 10 liter of water he drinks it's not ethical to offer this type of things or at least you should get more than one dollar but still I offer him one Dominican dollar Dominican dollar If he if he drinks 10 liter of water and I don't know somehow he gets interested into this start drinking tap water pure water without any solids now he is drinking water water water what is being added here now yes my friends yes water extracellular fluid become more watery right he's taking water without solute water is absorbing from git and going to his extra solar fluid after about two liter three later he say I don't want to have continue it's okay but still he has added lot of what water here now it will become diluted or concentrated diluted when it will get diluted right what will happen that osmolarity which was previously 300 now it has dropped to Let's suppose 280. thank you now under these circumstances when extracellular fluid osmolarity has dropped from 300 to 280 but intracellular fluid osmolarity is the initially same 300 now which fluid is hyper or smaller interest intracellular or extracellular s yeah intracellular is hyperosmolar more solute here so it will suck the water from which direction from water will move from extracellular fluid to intracellular fluid extracellular fluid will start shrinking intracellular fluid compartment will start expanding until when it will shrink it will go to maybe 290. and because it is getting the water it also it gets little bit diluted and it becomes also 290. when both of them become what equilibrated right the net movement of the water will stop so what we are seeing that when we change the remember basic concept normally in steady state intracellular fluid osmolarity and extra cellular fluid osmolarity are absolutely equal when you disturb of similarity on one side that will make the water shift in between the compartment so that again a steady state should be achieved in which osmolarity intracellular and extracellular should become what equal does that right so whenever you will make extra solar fluid hyper or smaller it will suck the water from intracellular to extracellular if due to some disease process if you make extra cellular fluid hypos molar less or smaller then water will be sucked by the intracellular compartment from the extracellular so I just say something now I'm going to put a question there is a person who has a some disease process going on and due to that disease process extra solar fluid become hyper or smaller what will be the shift of the water from if extracellular fluid has hyperosmolar what will be the shift of the water from intracellular to exercise now there is another patient who has a disease in which extracellular fluid become yes hyposmolar now fluid will shift from intracellular to hey you are intelligent good excellent so you know that that when it become hypo smaller water will move to the hyperosmolar side is that right now let me tell you some interesting thing let's suppose I add through this lesson through this intravenous line I add sodium chloride solution and this sodium chloride solution Sodium Chloride solution is called saline what is it called saline saline solution no lesson if you have pure water let's suppose I have a pure water in this container pure water has no smallity it doesn't have any of smaller power now I want that this pure water should have same or small larity it should have same osmolarity as my extracellular fluid and intracellular fluid normally my extracellular intracellular fluid have how much osmolarity 300 300 so if I want that this pure water should have the same osmolarity as as my body fluid then I add what is it sodium chloride into it what I'm adding sodium chloride into it when I add sodium chloride into it it will become more and more or smaller until a time will come there's so much sodium chloride is added that this water also become 300 billios molar per liter is that right when so much sodium chloride is added that this water become have the same osmolarity as my body fluids I will say this say line is ISO or smart Tech isomin same it has the same osmotic power as my water compartment fluid compartment so what is ISO osmotic Saline saline which is having so much sodium chloride that its osmotic power is equal to about 300 Milli or small is that right we also call it isotonic what we call it isotonic saline so what is isotonic saline isotonic saline is that sodium chloride solution in which so much amount of sodium chloride is present which is able to exert a smaller pressure of about 300 Milli or small this is isotonic or isosmotic Amic layer how much sodium you need to add here now this is the question how much sodium you are supposed to add the amount of sodium to be added to one liter of water to make it ISO or smaller with our body fluid as the amount of sodium is 150 millimole so what does it mean that if you take in one spoon you know spoon you eat kuchara okay spoon in one spoon if you take what 150 Milli mole of sodium chloride is that right A Milli right and add to one liter pure water this will make the solution isothermic is that right this is the relationship between the amount of sodium and a smaller power now another thing if I rather than 150 I add only 75 Milli mole of sodium chloride then osmolar power here will be 150. do you think now it is as or smaller as body fluid no it is called it is having half osmolarity than body fluid that osmotically active particles in this solution when some primary mole of sodium is chloride is added osmotically active particle then this solution are half than the osmotically active particles in our extracellular intracellular fluid so this will be called half saline the term which is used here is half saline and this half cell line is isotonic hypotonic or hypertonic hypotonic it has tone less than the normal body fluid is that right now imagine if I add too much salt let us suppose I add if one spoon if one spose one spoon is 150 millimole if one spoonful of 150 millimole of sodium chloride add it to one letter we make the solution we make the saline isotonic if we add half spoon it is hypertonic saline and we add two spoon it is do you really understand now look on the experiment I don't know I love to teach I should have to do something about this love listen carefully now we have three containers we have okay three intravenous IV infusion baths right here it is yes here it is normal saline normal Saline you understand it it's osmotic osmolarity is 300 Milli or small and amount of sodium added is 150 millimole per liter of course are you understanding this is hypo okay and of course this should be called normal saline should be called ISO tonic is that right this is having less sodium chloride so what is this hypo tonic let's suppose here the osmolarity was 300 Milli or small per letter here it is 150 Milli yes a small per liter so it is half normal saline and here we have added too much salt it become hyper yes tonic let's suppose in this solution Sodium Chloride is 600 Milli or small per liter is that right it is doubles a line now imagine what really happens when one of these is given given to a person this is your drip number intravenous inferior number one two three let's suppose if we connect this to this person there's a stopper here we open the stopper if this fluid is going here we are adding to intravenous line and from it will add first to the blood you know sodium chloride solution will come to the blood but because sodium and chloride is equilibrium to both sides So eventually sodium chloride concentration and interstitial fluid and plasma will be the same so we say truly this solute and water is added to both sides to the extra solar fluid when this will come okay he says that this experiment should be told after the break let's have a break let's continue our discussion about the body fluids compartment so we were talking about that here's intracellular compartment which is of the fluid which is com surrounded by the cell membranes right and here is extra solar compartment which consists of interstitial fluid and plasma but interstitial fluid and plasma except the plasma protein then cells present in the blood other component can easily Exchange in between the interstitial fluid and the plasma now as I told you previously the normal osmolarity of the plasma is 300 osmolarity of interstitial fluid is also 300 so we can say osmolarity of extracellular fluid is 300 in normal healthy steady state situation osmolarity of intracellular fluid is also 300 Milli or small per liter right now we have prepared three saline solution that in the water we have added the sodium chloride in this container number B we have added water with 150 millimole of sodium chloride when one liter of water is added one 50 Milli mole of sodium chloride so naturally sodium chloride dissociate into sodium and chloride so both of them observe the osmotic pressure and osmolality of osmolarity of this fluid becomes 300 Milli or small and when a saline solution has osmolarity of 300 Milli or small it has the same osmolarity as our body fluids so we say such saline solution is isotonic with our Body Solutions but let's suppose rather we add to container a half amount of the sodium chloride then osmolarity of this solution is 150 Milli or small which is half than the normal saline so such solution can be called half normal say line or because this saline solution has less amount of sodium chloride so it is less of having less osmotically active particles as compared to the normal saline or as compared to our body fluid osmolarity so we can say solution a is hypotonic Saline then we can prepare one more solution or saline solution in which we add too much sodium chloride and we keep on adding sodium chloride until osmolarity of this solution becomes 600 Milli or small per liter now this solution in the C container is having double osmo osmolarity as compared to our body fluids so we say this is a hypertonic Saline have you understood well these three solutions now let's come back to this diagram in this diagram on x-axis I'm showing the volumes and on y-axis I'm showing the osmolarity now osmolarity here is 300 Milli or small for example if solution had 100 Milli or small it will be here 200 Milli or small here 300 here suppose 400 here so whenever our body fluid has increases polarity it will move towards above the 300. whenever body fluid has lessons molarity this is our Central Point normal it will move downward whenever volume will expand it will move on these sides volume if it expands it will move on this side if intracellular volume expand this is the central point intracellular fluid expand it will move to this side is that right so again the volume is on the x-axis the central point is here and whenever extra cellular volume expand this is moving away from the central point right and if extra cell volume shrink it will move in this direction when we talk about intracellular fluid compartment when intracellular fluid compartment expand it will move away from Central but when uh internal fluid compartment will shrink it will move towards the Central Point am I clear now we start our experiment it's very simple let us suppose we start adding fluid number one now now fluid a is hypotonic Saline it has less sodium chloride as compared to our body osmotic power now when this solution let's suppose we open this topper and we have closed this if this solution is coming here now this drop of fluid which is coming here it is having how much osmolarity 150 it has less osmotical power so as this fluid will keep on adding initially it will add into blood compartment but because sodium chloride and fluid can freely move between the plasma and the interstitial fluid So eventually this fluid which is coming from container number a it will distribute and equally braid and between the whole extra solar fluid but when sodium you know can sodium go in no so all the sodium which is coming with this sodium chloride it will end this normal saline it will be added to extra cellular fluid so first event the first event is the change in the first change in the exercise of fluid is that hypotonic solution is coming when a hypotonic solution is coming or similarity of this fluid will go up or down it's very simple before this fluid came what was the osmolarity here 300 okay both of them have a similarity of 300 when this fluid came what is the Solarity of this fluid 150 so when both of them will mix a similarity will go up or down it will go down you are not understanding me it's like that that you have a very very salty water and to very salty water you add less salty water and combination will have osmolarity plus am I right so when a solution is added to extracellular flow head the total osmolarity of this fluid will drop total osmolarity will drop when osmolarity will drop under these circumstances the second important point is we have to look at what happens to fluid shift again what is happening that hypotonic solution is adding which is a hyposmolar so normal or smaller extra solar fluid is mixing with high post molar intravenous fluid and the similarity is becoming less so external cell of fluid become hypo or smaller then it becomes hypo smaller osmolality of external fluid will go down right so rather than here it will become let's suppose here is that right now what will happen that when it becomes hypo smaller right water will move in which direction in between these two compartments it will move from hyper smaller to normal smaller which is relatively hyper so water will start moving in this direction when water will start moving in this direction what will happen to this area it will become also hyposmolar it was 300 its osmolality will also start coming down let us pause its osmolality was 280. when we added here first change but when water will start moving here it will start coming down it will become too 90 and its osmolarity will go little bit up maybe it also becomes too 90 because water is leaving so until both of them equilibrate then shift of the water will stop but during this process what has happened that what is this compartment what is this compartment intracellular intracellular compartment osmolality went down so we can say not osmolality is not at this level because similarity has become less so when we added hypotonic solution to the extracellular environment osmolality of extracellular apartment dropped is the right then water from high concentration move to the low concept constant you are telling me right from high concentration to lower concentration or from lower smaller area to higher smaller area and then this also become diluted right and here also intercellular similarity also drop but what really happens to the volume of intracellular compartment what happens to the volume of intracellular compartment this will expand in this direction so it will become like this Hammer class that volume of intracellular compartment will increase and volume of extracellular already increased because water came water and solute both came is that right so a net result will be let me make the diagram here this was the original situation when you added hypotonic solution now the new situation is when you added hypotonic osmolality went down here it came down and then when water shifted here all those molality became down and this expanded to that side and because water has also come here all the water which came here some of it has gone here some is left here so it also expand to this side are you understanding so what happened we say intra initially so in three step understanding three step number one what initially happened to extracellular fluid the hypotonic solution came and osmolarity of the solution went down when it became hypo smaller right then Water started shifting from the extra solo compartment to intracellular compartment this is the second shift right with that it will water will keep on shifting until both osmolality become equal so both of them become less than normal but total amount of water which was added here total amount of water which was added here some of them remain here and some of the water has gone here so both compartment expand am I clear no problem into this okay now we do another experiment in this experiment we never give the solution to the patient now this is us another solution R and now we are going to use the solution number B right we are going to see what happens there we go back towards normal diagram now we are adding which solution solution number B when solution number B is going okay I will make a small diagram here solution number B is adding here now the drop of water is coming from say line now this solution has same osmolarity which is the osmolarity of extracellular fluid are you understanding when isotonic fluid isotonic fluid is added to what extracellular fluid will osmolarity change will the osmolarity change no osmolarity of this will still remain 300 because the solution with osmolarity of 300 has been receiving another amount of solution with the same osmolarity so total fluid which is mixture of extracellular fluid plus added normal saline total fluid will have the osmolarity of 300 is that right because after the B solution is coming here osmolarity does not change in extracellular fluid do you think there will be any shift out of it there will be any shift of the fluid between inter solar and Excel solar no because shift of the fluid is controlled by osmolarity because when you add B solution here right and osmolarity of extracellular fluid and b b c line is the same normal saline osmolarity isotonic fluids osmolarity and essential fluid is same so there's no change in the similarity of this so it remain at its normal position this time right because its similarity does not change so it will not allow any movement of the water across the membrane but this sodium chloride is coming along with the water but this solute stay here along with this one liter of whatever amount of water is coming that is added only to the extra cellular compartment so under these circumstances what really happens that it expands look what is this osmolarity remain the same right there's no change in what intra cellular compartment but in extra solo compartment because we have added this fluid so it will expand in this direction so what is happening whenever you give isotonic fluid to the body whenever you add isotonic fluid to extracellular compartment right isotonic fluid isotonic saline what really happens that solute and incoming water add to extracellular compartment and expand the extracellular compartment but because of smallerity of external compartment does not change so there's no shift of the fluid between extracellular compartment and intracellular compartment am I clear no problem into this another thing I did not mention about the RBC about red blood cell the osmolarity of the fluid within the red blood cell is also 300 you know red blood cells are also like cells and oscillarity of intracellular fluid of red blood cell is how much 300 because fluid which is coming here this fluid has also 300. the fluid which is added it has a similarity of 300 accessible fluid has also 300 this is also 300. do you think Red Cell will shrink or expand no because this fluid which is coming here it is not changing the it is not changing the osmolarity of the plasma because it is not changing the osmolarity of the plasma so plasma similarity remains 300 and intra RBC osmolarity is also 300 so there's no change of the exchange of the fluid a shift of the fluid between the RBC and the plasma or will there be any no so these cells will not shrink and not expand is that right but in previous experiment we said that hypotonic solution was coming in previous experiment so we were making the solution hypotonic when the solution become hypotonic you remember in previous experiment we said fluid will shift from extracellular to Cellular compartment fluid will also shift in hypotonic situation to the rbc's also and rbc's will swella in previous situation they are water will enter into rbcs in previous if this container is working these two are not working it is becoming hyper hyposmolar if this solution is coming and this is becoming two suppose this become 290 and of course water has shifted here and this also become 290 or less and because it is 300 so water will shift n to make it also 290 and RBC will swell up are you understanding so what really happens when rbcs are suspended in isotonic solution if rbcs are present with this solution no change in RBC volume in rbcs are suspended in this solution what will happen to RBC they will absorb the water and swell up and the pharmacies are suspended in this solution water will go from the orvises to the hypertonic solution you are understanding and rbcs will shrink am I clear really now you just now we come to the third situation let's suppose we come to the third situation now everything is again normal again we make everything normal right and we do one thing now these two solutions are not moving and all compartments are with normal volume and normal osmolarity and to this person now we are adding solution number c then C solution is going what we are doing hypertonic saline hyper or smaller fluid is mix mixing with extra cellular fluid can sodium now the fluid which is coming with this This is highly concentrated hyper or smaller is that right now this fluid which is coming here do you think it's sodium and chloride can go into self no so whatever sodium chloride is coming here now in a way we can say when this solution is coming which is solutes are coming more and water is coming less it's the concentrated in this case solute and water are coming with the same ratio as body fluid in this case solute were coming less than water was coming more is that right but again now this in this case there are too many solute it is hyper or smaller solution hyperosmolar Solutions are mixing with normal smaller extra solar fluid the total osmolarity will go up in this case first event is when hyperosmolar solution is coming to extra solar compartment and sodium chloride or the solute cannot equilibrate with the intracellular compartment it will become what hyper or smaller osmolality will move up when it will become hyper or smaller when it will become hyper or smaller what will happen to the what is this this fluid this will move from intracellular compartment to extracellular compartment and its osmolarity will start going up so this volume will move to this direction so what will happen it will become like this you know that intracellular compartment fluid is Shifting to the extracellular because it is having more osmotically active particle should suck the fluid from Interstellar to extracellular right until it goes up and this was already it was very high let's suppose it has gone to 360. after the this solution and it is osmolality of 360 here it was 300. water start moving in this direction until it becomes suppose 320 and this also drop to 320. so both of them are having highest molarity of 3 20 right and because fluid has shifted to that direction so what has happened intracellular compartment has sharankan but extracellular compartment is flu got fluid from the solution as well as from this side so it's fluid will increase so it will shift like this then this new diagram what else is showing the dotted lines that extra solar flow fluidus molarity has gone up plus external fluid what volume has gone up intracellular fluid osmolarity has gone up but volume has gone down am I clear is it really clear right if all these things are clear then we can move forward the certain clinical situation let's have a break for five minutes thank you now we will discuss the volume changes and osmolarity changes in our body fluid compartments when there are some physiological disturbances right that how different physiological disturbances alter the volume changes and osmolarity changes in our body fluid compartment but before really I go for that I will explain few terms which are very commonly used right again let's go back to basic diagram right this is total body fluid this one is intracellular fluid here it is extracellular fluid having the blood here and interstitial fluid here and this is the axis for osmo clarity and from here we are talking about volume is that right now few terms which I will explain number one in the medical literature when we talk about that volume of a particular compartment depends on which factor what will be your answer the total volume of fluid in a specific body fluid compartment mainly depend mainly depend on which factor it depends on the solute it depends on the osmotically active solute particles that's it the single answer next time again the volume of a suppose extracellular fluid volume depends on which factor that depends on the solute particles if solute particles become more volume will become more if solute particles become less volume will become less so principle number one principle number one is that volume of body fluid compartment mainly depends on yes osmotically active osmotically yes solute particles and you have to remember the most important solute particles in extracellular fluid is sodium chloride that's it principle number two principle number two is what is meant by osmolarity because presence of solute particles make the fluid the presence of solute particles in a fluid determine the osmolarity of the fluorine so what is meant by osmo clarity yes what is your concept of osmolarity the number of number of osmotically active particle in a solution are expressed in term of ocularity when we say that osmotically active particle in a solution are going up between osmolarity is going up and if number of osmotically active particle in a solution are becoming less so we say fluid or similarity is becoming less so what is the Solarity we can say that concentration of osmotically active particle is expressed as units of osmolarity and what are the units of osmolarity in the body we use the units are Milli or small per letter now what is the difference in osmolarity and osmolality yes what is the difference between osmo clarity and osmo reality yeah of course one difference is spellings what are the differences yes anyone anyone that's very simple it is the osmotically active particle per letter and this is osmotically active particle per kg kilogram that's it right so what is there that for example if I say that our body fluids have 300 million Smalls per liter of the water this is osmolarity and if I say listen if I say that my body fluids have 300 Milli or small per kilogram of water I'm talking about osmolality for practical purposes water can be measured in leader as well as kilograms and one liter of the water is equal to one kilogram of water one liter of water is practically equal to one kilogram of water so for practically in our body osmolarity and osmolality is same am I clear for example we say so much sodium is added to one liter of the water so much sodium chloride is added to one liter of the water that osmotic power is 300 Milli or small per liter if we are talking per liter of water it is osmolarity but if I say so much sodium chloride is added to one kilogram of water one kilogram of water we have added so much sodium chloride that now osmotic power is 300 Milli or small but because it is per kilogram then we'll say this is water osmo lality in our body in medical term doctors have decided to measure the things per liter so we use the term osmolarate is that right amicler so this was something about osmolarity and I already have told you normal osmolarity of the body fluid is to be very specific it is about to 90 Milli or small per liter but for a generalization we use the term 300 Milli or small per liter am I clear then the third term which I want to clear is what is the concept of steady state in steady State the steady state between the intra cellular fluid and extra cellular fluid steady state is a situation in which an equilibrium is achieved between the intracellular fluid and extracellular fluid in such a way that there is no net movement of the water it means in steady state osmolarity of extra solar fluid and intracellular fluid will be equal normally in every person and extracellular fluid and intracellular fluid are present in steady state and steady state what happens osmolarity of extracellular fluid and intracellular fluid is equal and there is no net movement of the fluid but of course when there is some physiological disturbance right then osmolarity may change osmolarity of excess cellular fluid may change in some physiological disturbance then osmolarity changes in extracellular fluid the fluid shift occur between the two compartment to achieve a new steady state for example if osmolarity is normally here 300 but if it becomes 270 then fluid from will start shifting from extracellular fluid to Interstellar fluid until both of them achieve a new steady state at a new or smaller level is that right or if osmolarity due to some physiological change osmolarity of extracellular fluid becomes 330. then fluid will start moving from intracellular to extracellular to achieve a new steady state until again osmolarity becomes equal on both side and net movement of the fluid stop am I clear so normally our body fluids both compartment are in steady state steady statement to take number one osmolarity on both sides should be equal and there should be no net movement but when there is some physiological disturbance and osmolarity changes in extracellular fluid body come out of steady state fluids start shifting across the compartment until a new steady state is achieved in which again osmolarity in the extracellular fluid and Interstellar fluid become equal and with the new volumes adjusted third thing a common term is used in medical literature volume contraction or volume expansion volume contraction and volume yes expansion now this is very important to understand it clearly when I say in my patient there is volume contraction and I am referring to the volume of extracellular fluid for example in some physiological disturbance extracellular fluid volume increases right when its volume increases I say there is volume what is this I use the term volume expansion actually I should use the term extracellular volume expansion but in medical literature commonly when we say there is volume expansion it means we are referring to expansion in the volume of extra solar fluid this term may not include what is happening to intracellular flight then if I use the term volume expansion the volume is increasing I'm referring only to extracellular fluid volume if I say there is volume contraction again I am referring only to the extra cellular fluid volume its bit you can say unfair with the intracellular fluid because sometimes what happened accessible volume expanded an intracellular shrink but the term will be used only that patient has a what volume expansion is that right so whatever changes occur in both these of compartment in medical literature we use in term of extracellular fluid if I say that my patient has volume expansion which volume is expanding if I say my patient is volume contraction which volume is contacting extracellular whatever happened to intracellular we are not referring it's unfair but this is like practical life right then we come to another term we are talking about osmo osmo larity there are three terms we use normal smaller normal smaller or smaller hyposmolar and hyperosmolar or when there is high post molar we also called a hypertonic hyper tonic and if there's a hyper or smaller we can also use hyper tonic now let me make a diagram here and explain what is meant by these terms if also I say my patient have hyperosmolar situation I say my patient has hyper or smaller situation I'm talking about osmolarity of extracellular fluid if is if I say my patient is normal smaller I'm talking about a gain of similarity of if I say my patient is hyposmolar I'm talking about osmolarity of extracellular fluid so actually when we are using the term of high normal smaller or high post molar or hyper smaller these terms are referring to osmolarity changes in extracellular fluid and external fluid is osmolarity remain at this level it is normal smaller if a smallerity goes up this is hyperosmolar if osmolanity goes down this is hypo or smaller is that right now let me tell you if I tell you that my patient has hyper osmotic or hypertonic volume expansion look I'm writing a situation here star number one my patient has hyper osmolar volume X expansion what this term mean that my patient has extracellular fluid in which osmolarity is more than normal and volume is more than normal is that right if I write another term that my patient has hypo or smaller or a hypotonic volume expansion what does it mean again both terms are referring to extracellular fluid that my patient has what hyposmolar High less osmolarity of excessive fluid and volume expansion of the extracellular fluid am I clear no problem into these terms right now if I say my patient has isotonic or isosmolar volume expansion what does it mean osmolality osmolarity of extracellular fluid is normal but volume has been expanded so it means if extracellular fluid has volume expansion we will draw it like this is it right it is volume expansion if extracellular fluid is volume expansion this may be I saw smaller volume expansion isotonic volume expansion or it may be hypertonic volume expansion it may be hypotonic volume extension if this is the change okay let me make it more clear to you people this is the standard right if I say that my patient has volume expansion like this what is it isotonic volume extension if I say my patient has like this what is it hypertonic volume expansion if I say my patient has these terms are really clear to you and of course there can be other situations also let me draw another diagram now you will tell me in in my patient extracellular compartment has become like this what is it High post molar volume contraction if I say that my patient is like this isotonic volume contraction and if I say that my patient is like this what is it hypertonic volume contraction so volume contraction may be volume look from this side volume has come here so all of these cases are volume contractions right but this is hypotonic volume contraction this is otonic and this is I am a really clear right let's have a break