Electrolytes in the ECF and ICF - Sodium, Potassium, Chloride, Calcium, HCO3 - Homeostasis

hey guys it's medicos is perfection Ellis this is the third video in my series on electrolyte disturbance fluids acid-base disturbance today we'll talk about electrolytes in the extracellular fluid as well as the intracellular fluid [Music] during this Super Series we're gonna talk about all of the stuff but we are still here I've talked about cell membrane transport in the first video so make sure to check it out 60% of your total body weight is made of water 40% of your total body weight is in the intracellular called ICF and 20% is the extracellular and then we have 15% here and 5% here if you are hundred kilograms weights the plasma will gonna be five liter but if you are a typical male 70 kilograms or 60 kilograms the plasma is gonna be three first let's answer the question of last time so how many liters of normal saline do you have to infuse the patient in order to deliver one liter to its plasma compartment as you know normal saline is isotonic has the same tenacity or osmolality as the plasma so the correct answer is four liters let me explain why as you know total body water is 60% of your body weight 40% of your body weight in the intracellular fluid and 20% is in the extracellular fluid of those 20% you have 15% of the total body weight is in the interstitial space and 5% is in the plasma the ratio between the plasma to the interstitial space is one two three very nice so let's infuse one liter of normal saline into this patient we infuse fluids through the IV line they will go first to the plasma but then it has to equate okay with the interstitial space until equilibrium occurs so this one later one two three ratio so 0.75 liters is gonna go to the interstitial space and quarter of a liter is gonna stay in the plasma let's infuse two liters to this patient so now we have one and a half liters in the interstitial space and here we have half a liter in the plasma cell we haven't reached the 1 liter yet let's try 4 liters of normal saline when you infuse 4 liters what will happen 3 liters is gonna stay in the interstitial space and 1 liter is gonna stay in the plasma which makes 4 liters of normal saline the correct answer in order to deliver 1 liters in the plasma ok electrolytes or ions some of them are more prevalent in the extracellular fluid others are more prevalent inside the cell or in the intracellular fluid very cool so how to memorize them I have a crazy mnemonic for you if it starts with a P it's more prevalent in the intracellular fluid ok potassium starts with the P phosphate starts with the P proteins start with the P but how about magnesium so I invented something magnesium is released from the super nova explosion and it's also used in photography now the digital photography no no no back in those old days in flash photography fluids and electrolytes what the flip is an electrolyte electro means electrical light means substance that can be decomposed so electrolyte is gonna be decomposed by electricity so electrolytes are electrically charged molecules in short electrolytes are the same thing as ions so here's the hydrochloric give it some electricity to dissociate into protons and chloride why do we call the positive ion cation because it's attracted to the cathode cation the cathode is the negative Pole and why do we call the negative charged anion because attracted to the anode the positive pole if you didn't know that there is no hope for you sodium is the major cation which means a positive ion in the extracellular fluid outside of the cell let's use the Socratic method why because of the sodium potassium pump it pumps three sodium outside the cell and two potassium in the cell second potassium is the major cation in the intracellular fluid why due to the same flippin reason next chloride is the major anion in the extracellular fluid why is that because you have the sodium potassium pump it pumps sodium outside of the cell when you pump sodium three sodium out and two potassium in it's as if you're pumping one positive ion outside the cell so the result is more electro positivity outside the cell and more electro negativity inside the cell when the outside of the cell is more positive it's gonna attract the negative chloride from inside the cell to the outside that's why chloride follows so sodium chloride loves sodium sodium and chloride are like a husband and a wife they combine together I mean emotionally of course okay chloride follows sodium let's go to phosphate phosphate is the major anion in the intracellular fluid why because we need phosphate inside the cell to form ATP ADP plus B equals ATP energy we need phosphate inside the cell to bind glucose glucose into glucose 6-phosphate was the first step in glycolysis if you remember your biochemistry and I told you a mnemonic before phosphate fix stuff it fix glucose inside the cell by converting it into glucose 6-phosphate glucose alone can go inside the cell and can go outside the cell again this is not how we use glucose we need to fix it inside the cell we buy it with phosphate your professor probably told you Oh sodium is more common outside of the cell chloride is more common outside the cell potassium and phosphate are more common inside the cell but nobody has told you why I don't memorize medicine I understand medicine is common sense but unfortunately common sense is not common anymore so let's take it to the next level and tie it to internal medicine there is a syndrome called refeeding syndrome let's say that this young lady had anorexia nervosa her BMI is 14 she's so thin she doesn't eat so you told her we're gonna keep you in the hospital and take care of you and you keep feeding her and feeding here and feeding her excessively because you are stupid and now the body which was hungry for energy is gonna release lots of insulin to build up stuff proteins carbohydrates and lipids mitochondria is gonna work like crazy to provide energy so that insulin can perform its job the mitochondria is using lots of phosphate to form ATP phosphate is gonna move from the extracellular fluid to the intracellular fluid leading to less phosphate outside called hypophosphatemia you have depleted all the phosphate you cannot form any more ATP leading to no enzyme activity this could be fatal you're a crazy doctor you are a stupid because you thought that feeding a thin lady is suddenly gonna give her curves you're only gonna curve the phosphate out of her ECF and curve the life out of her stupid actions have consequences and so do pumps the sodium potassium ATPase primary active transport needs energy and carrier 3 sodium out 2 potassium in 3 positive out to positive end the net is 1 positive out and 1 negative in the one positive out is gonna pull chloride outside of the cell more positivity out Pole's chloride forming sodium chloride can pull water by osmosis in certain tissues you have electro negativity inside called the resting membrane potential this is the basis of action potential and sign apses and all of this crazy stuff in excitable tissue such as nerve and muscle you can have sodium calcium anti port ok which is a different channel what type is that this is secondary active transport sodium in calcium out secondary active transport quick review why is more sodium out because of the sodium potassium pump why is there more potassium in sodium potassium pump chloride follows the sodium phosphate because we need four ATP glucose outside because once glucose entered the cell we converted into glucose 6-phosphate thank you phosphate so there is no glucose inside the cell it's just glucose 6-phosphate by definition glucose is more common outside the cell by carbon is more common outside the cell because we call this the alkaline reserve and we're gonna talk about this soon let's talk about metabolism particularly catabolism you have carbohydrates fats and proteins this is your food incomplete metabolism gives you from polysaccharides to monosaccharides glucose fructose galactose complete metabolism ATP very well done water and carbon dioxide fats will give you fatty acids and ketones acetone ysidro citric acid be reduction butyric acid complete when you have glucose the complete will yield ATP you well done water and carbon dioxide proteins amino acid alpha keto acids ammonia ray uric acid carbon carbon dioxide sulfur gas and phosphoric acid if you pay attention everything here is an acid you have fatty acids keto acids keto acids and you have carbon dioxide which we consider in medicine as an acid and I'll tell you why and uric acid sulfuric acid phosphoric acid and here is all of your biochemistry book in one slide carbohydrates fats proteins as SoCo a Krebs cycle also known as TCA cycle or citric acid cycle producing ATP and as you know the Krebs cycle has lots of acids as citric acid I so see Ettrick acid alpha ketoglutarate acid fumaric acid etc when there is no oxygen there is lactic acid in short metabolism produces acids why do we consider co2 an acid this is called the golden equation co2 Plus water carbonic acid dissociate into bicarbonate and proton so co2 carbonic acid proton which is the ultimate acid that's why co2 is considered an acid it's not an acid by itself but it yields acid so in medicine we are like clinically significant stuff oriented so carbon dioxide is an acid co2 is volatile the lung is gonna handle this bicarbonate is non-volatile the kidney is gonna handle this this is the called an equation so what's the moral of the story metabolism produces acids where does metabolism take place scientist all or mitochondria both of them are inside the cell that's why the ICF is more acidic because metabolism is acids that's why the ECF contains the alkaline reserve also known as bicarbonate to buffer the acidity inside the cell that's why your blood pH is normally slightly alkaline 7.4 you know that your blood pH is 7.4 but you have never asked yourself why is it alkaline not neutral because you have an alkaline reserve there is no such thing in your body as an acid reserve it will be an oxymoronic thing we don't need acid reserve we have lots of acids already we need an alkaline reserve to buffer to neutralize the acid quick pharmacology ty you have the sodium potassium ATPase sodium out potassium and beta agonist stimulates this channel leading to lots of potassium in which means less potassium out hypokalemia let me ask you two simple questions let's say that you have a syringe and it contains 100 MLS of fluid the concentration of sodium chloride in the fluid is 6 milligrams per ml question calculate the amount of sodium chloride in the syringe now pause and the answer here it's easy amount if you have 6 milligrams per ml and you have hundred MLS 100 times 6 equals 600 so hundred watt six hundred milligrams it's very easy what did you do you did this amount equals volume times concentration boom second question suppose that you will infuse sodium chloride in this wrench and that amount is 14 the volume is 10 what's the concentration of sodium chloride per ml pause and the answer is concentration equals you have 40 and you have 10 MLS per ml so over 10 and the answer is 4 what did you do you got 40 which is the amount divided by 10 which is the volume so concentration equals amount over volume amount volume times concentration concentration amount over volume now we know why concentration of any solute such as sodium chloride is measured in milligrams per liter amount divided by volume amount divided by volume concentration of an electrolyte such as sodium which is a positive ion is measured in Mellie equivalent per liter again Mellie equivalent is an amount later is a volume amount over volume why not milligram per liter in case of an electrolyte because electrolytes have different chemical properties we call it milli equivalent which means it's the equivalent to 1 milligram of hydrogen so Mele equivalent per liter because any concentrations amount over volume so if you look at the measuring unit the measuring unit of amount amount is the same thing as mass its milligram or gram or kilogram whatever volume milliliter which is the same thing as cubic centimeter you idiot or liter concentration mount over volume any amount over any volume in your exam when they give you like a lab reference with all the normal values they give you two measurement or two measuring units first one is the male equivalent and the second was Melly mole per liter so if you are mono valent it says sodium potassium chloride hco3 mono valent which means you remember so here are two electrons in the first electron shell then you have eight electrons then you have one electron in the outermost shell we call the amount of valence of your memory of chemistry so if you are mono valent the concentration in malenko's and per liter will be the same as Mela mole per liter why because milliequivalents per liter equals mela mole per liter times valency when your mono valent valency is one so this equals this if you are divalent such as magnesium the concentration will equivalent is double the concentration only more you don't believe me okay look at the normal serum sodium concentration it's around 140 ml equivalent per liter let's measure it in milli mole per liter it's the same thing now let's go to magnesium normal serum magnesium concentration is two moly grams per deciliter but one millimole per liter it's double because magnesium is die feeling nobody will ever tell you this because nobody has a clue should you memorize the numbers of concentration in the extracellular or the intracellular the answer is the extracellular why because when we draw blood from the patient we draw it from the plasma which gives what it's part of the extracellular fluid so to memorize them there is the rule of four normal serum sodium concentration 140 chloride 104 potassium 4 and bicarbonate is 24 and pH is 7 point 4 you're welcome I know that many people cannot sleep because they keep thinking of the law of electro neutrality which states in any single ionic solution the sum of negative charges attracts and equal sum of positive charge in médicos this language cat x equals n ions so if you have three positive cations you should have three negative ni very nice so in the intro extracellular fluid outside the cell domain cation is sodium main anions are chloride and bicarbonate the difference between them is called the anion gap the anion gap is not an actual gap it's a gap in our measurement this is a very deep philosophical statement but when we talk about the anion gap I'm gonna explain how and I'm gap equals sodium minus chloride plus bicarbonate the positives on one side the negatives on the other side due to the law of electro negativity sodium what's the function fluid regulation osmosis it pulls water if you have sodium disturbance the cell will swell or shrinks if it happens in your brain you have mental status abnormality because the neurons are swelling or shrinking this is so bad mnemonic sodium CNS problems potassium resting membrane potential disturbance in potassium membrane potential problems in the heart we call this a arrhythmia a means no read me means rhythm mnemonic kalium cardiac problems kalium of course is potassium calcium less calcium lead to increase permeability to sodium more sodium more action potential which lead to more excitability so when you are hyper excitable leading to tetanic contractions confusion spasm seizure those are the symptoms of hypocalcemia in cases of hypercalcemia there is decrease permeability to sodium decreasing the action potential leading to decreased excitability increase calcium will lead to less excitability everything is slow everything is hypo fatigue lethargy even your intestines are slow constipation mnemonic calcium contra excitability because it goes against the excitability less calcium more excitability more calcium less excitability magnesium like calcium it is stored in the bone affects the activity of transport of sodium and potassium sodium and potassium gives what disturbance magnesium will lead to nerve and muscle excitability problems and the brain is called delirium tremor and Sydney in the heart arrhythmia and prolonged QT chloride just follows everybody fast for us is found in the form of phosphate such as this and this we call this dye basic phosphate this tri basic phosphate in bones and teeth loves binding to calcium it forms ATP DNA RNA and it's a famous buffer let's phosphate less ATP less enzyme activity which will lead to less metabolism you have symptoms of servation less oxygen transport you have symptoms of hypoxia less white blood cell function you have infection let's blood calling you bleed all of these were symptoms of refeeding syndrome remember refeeding syndrome hypophosphatemia if you have hyper phosphate indium phosphate binds calcium deposit in soft tissues leading to groans ECF ICF the osmolarity of the ECF must equal the Oz multi of the ICF so ECF is interstitial and plasma so osmolality of the interstitial fluid equals Oz multi of the plasma equals osmolality of the ICF why because otherwise water would be moving constantly to one compartment until you explode it's not how it works the osmolality has to be equal so that water movement is regulated and the net is zero what the flip is osmosis this is the topic of the next video here is a summary of today's video remember metabolism produced in acidic ICF but there is an alkaline ECF that's why pH is 7.4 co2 is considered an acid concentration of cations equal concentration of anions and the osmolality has to be 290 across the board as a clinician look at the measuring unit if it smell equivalent we're talking about an electrolyte into sodium chloride potassium etc if it's in milligram we're talking about solute such as sodium chloride so and here are the measuring units of an amount volume and concentration sodium CNS kalium cardiac problem scales contre excitability refeeding syndrome has hypophosphatemia don't forget the rule of force here are three questions for you four five and six the previous three questions were in the previous videos did you know that now you can go to my patreon page click on video notes and choose hematology for example you will see all of my hematology notes there are like one hundred and fifty of them you can download them print them view them do whatever you want go to patreon.com/crashcourse