hi everyone dr mike here in this video we're going to take a look at fluid balance and the first place to begin is reminiscing back to chemistry class do you remember sitting there peering at that giant poster on the wall called the periodic table which contains all the ingredients that we need to make everything in the universe did you ever sit back look at it and think how many of those ingredients or elements do i need to make a human well the answer to that is around about 59 of those elements we need to make uri but in actual fact to make around about 99 of you we only need six of those elements those six elements include in no particular order oxygen carbon hydrogen nitrogen phosphorus and calcium that's it these six make up around about 99 of you and in actual fact if i were to take two of these oxygen and hydrogen you'll find that they make up around about 75 percent of you most of the oxygen and hydrogen is actually snapped together in the form of h2o which we know is water which means around about 60 percent of you is water so what would that be you can calculate that right so i'm a 70 kilogram male 70 kilograms times 60 percent equals 42 kilograms i have 42 kilograms of water inside of my body where does this water sit well i'm not just a bag of water where it fills me from the feet up it's actually delegated or relegated to particular compartments what are these compartments well there's actually just two major compartments it's the area inside the cells which we call the intracellular fluid or it's the area outside the cells which has two subcompartments the area outside the cell is called the extracellular fluid and it's made up of the area outside the cells but between the cells called the interstitial fluid and the area inside of our blood vessels which we call plasma so you can see the various compartments of our body that contain water is inside the cells called the intracellular fluid or outside the cell called the extracellular fluid made up of two compartments the interstitial fluid which sits outside the cells but between the cells and also the blood plasma so how does this 42 kilograms fit within each of these compartments all right so of the 42 you will find that 28 liters of that sits inside the cells that's two-thirds 11 liters sits in the interstitial area and three liters sits in our plasma so two-thirds of our entire body water sit inside of ourselves the rest sitting outside in those two compartments what i want to do now is take a look at how do we maintain this 60 water how do we not lose too much how do we not gain too much what does the body do to maintain a balance so what i've done is i've taken this and i've redrawn it out here to show how we can take things in so intake and how we can lose this water so loss so let's divide this up into these three particular compartments so the first compartment i want to do is that of plasma so here is the plasma next is going to be the interstitial fluid interstitial and then the next is going to be intracellular i c f now a couple of things that you can see here is that when we intake water the first place it's really going to go is the plasma and when we excrete this water the last of the three compartments it's going to be associated with is the plasma as well keep that in mind the other thing is that in order for fluid to go from plasma to distinction to intracellular has to go through various membranes semi-permeable membranes so this one here for plasma it's this membrane here which is the capillary membrane so here at the capillary membrane what can get through this capillary membrane it's semipermeable we need to know this so what can get through the capillary membrane let's actually say what can't get through it makes it easier what can't get through generally are cells and large proteins they can't get through so cells and large proteins will stay in this plasma not necessarily crossing through to the interstitial area the area outside the cells but to go from the interstitial to inside the cells you need to cross another membrane which is this membrane here called the phospholipid bilayer let's write that down phospholipid bilayer and the phospholipid bilayer is another semi-permeable membrane what can't get through i always say the mantra if it's large or charged it's not getting through so that means proteins won't get through that means ions won't get through it charged atoms or elements like sodium potassium magnesium for example they won't freely pass through so that's another important point so before we move on to things like electrolytes let's talk about the water remember i said that from the plasma around about three liters of the water is sitting here 11 liters here at the interstitial and around about 28 liters here all right so let's now take a look at different ways that we can bring fluid into the body so we know that we can bring fluid in through the food that we eat and whatever we may drink and if you were to calculate how much you bring in per day it's around about 2 100 mils per day around about 2.1 liters another way is through carbon metabolism carbon metabolism so remember glucose is a carbon-based molecule we metabolize it at the electron transport chain of the mitochondria and we produce water doing this so carbon metabolism and how much do we bring in through carbon metabolism around about 200 mils of water per day which is a fair bit so cumulatively how much are we taking in around about 2 300 mils of water per day so how much do we lose then per day well let's take a look firstly how what are the different ways that we can lose fluid well you can have something called insensible insensible fluid loss now in sensible fluid loss includes it occurs mainly from our lungs so breathing and through our skin let's just write lungs down now how much do we lose through our lungs through breathing we lose around about 700 mils 700 mils per day just from breathing so remember when you bring in oxygen and bring out carbon dioxide it becomes humidified so water molecules get attached to it so you breathe out water now you can also have sweating and if you're not doing any exercise it's probably around about a hundred mils per day but if you are doing a lot of exercise that can be one to two liters which means if that increases you're gonna have to increase the amount of fluid you drink to balance it out right now in sensible loss we're simply talking about mainly here through our lungs now sweating that's loss and feces is another loss feces and we lose another 100 mils of water per day through our feces so together we've got 900 mils of loss here now the last way that we lose is through our kidneys so we obviously pee stuff out so we lose stuff through our kidneys that's around about 1.4 liters so let's write this the way we've written it 1 400 mils per day now if we were to calculate all this what you're going to find is that the loss per day 2300 mils per day so this is fluid gained this is fluid lost and this fluid water can move from plasma to interstitial no problem from interstitial to intracellular fluid no problem but there are things that influence the movement of water from these compartments which is the most important these predominantly are ions sodium potassium magnesium chloride for example they influence the way water moves inside and outside of the cell and between these compartments how let's take a look firstly let's go back and talk about the fact that water making up 60 of your body is oxygen and hydrogen snap together so let's have a look at that it's h2o so there's a hydrogen there's another hydrogen there's an oxygen and it's actually bound together in this boomerang like shape where the hydrogens have a slight positive charge associated with them and the oxygen has a slight negative charge what do you know about charges well negatives love positives positives love negatives so anything with a charge is going to love water and vice versa water's going to love anything with a charge which means when you ingest certain foods remember i said to make up a person you need six of those elements to make up 99 of you the rest can include some trace minerals things like sodium things like calcium things like magnesium and when they enter the body they gain a charge it can either be a positive or negative charge so for example sodium once it's inside the body it's n a plus chloride is cl negative magnesium mg2 plus calcium ca 2 plus these are just some examples of ions but because they have a charge water loves it the positive charge loves the negative oxygen the negative charges love the positive hydrogen so they are attracted to one another but think about this if i start to ingest a whole bunch of let's just take sodium for example i ingest a whole bunch of sodium and bring it in it first goes where into my plasma now can it cross from the plasma to the interstitial yes because the only thing that can't is cells and proteins so this sodium freely diffuses to the interstitium now i've got a high concentration of sodium here can the sodium freely move from the interstitium into the cell well no it's not large it's just an atom right but it is charged so this does not happen it cannot move through freely into the cell which means if you continually ingest or doesn't necessarily mean ingest do anything that changes the concentration of sodium in the interstitial area here so let's just say we have more insensible water loss through sweating the fluid volume in these two areas are going to drop which means if there's sodium in here concentration wise it's gone up now you might be thinking what are you referring to think about this as just a bucket of water think about your interstitial area as a bucket of water with some sodium in it now what if you were to simply take the water out so that there was a lot less water in here well the concentration of that sodium's gone up it was originally three particles per say five liters to now three particles per three liters the concentration's gone up and that's what can happen here through excessive sweating you might say but don't we lose sodium and sweat we do but we often lose more water than we do sodium you lose both but often you can lose more water you can also lose it through insensible loss so there might be some people in intensive care who have intratracheal tubes and the machines breathing for them sucking out a lot of that water making them dehydrated which means the concentration of these ions in the interstitial area like sodium it goes up but that sodium can't diffuse into the cell to balance it out so what happens is that the water inside the interstitial area gets dragged out to try and balance out that concentration the fluid is lost it goes oh i'll replenish some of it and the water drags out of the cells which means the volume inside the cells goes down and the cells become dehydrated so you can see here just by a quick run-through of showing where these ions can move and where they can't move altering the fluid balance it highlights the importance of maintaining adequate fluid volume also maintaining adequate concentration of ions and electrolytes as well so hopefully you enjoyed this mini lecture on fluid balance 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 tick tock at dr mike tadarovich at d-r-m-i-k-e-t-o-d-o-r-o-v-i-c speak to you soon