chapter 27 lecture 2 is on electrolytes electrolytes have four basic functions in your body they're going to help to control osmosis of water help to maintain acid base balances carry electrical current um that we need for Action potentials graded potentials uh hormone secretion neurotransmitters and uh as well as acting as co-actors for a number of different enzymes we express the concentration of electrolytes in Millie equivalents per liter for plasma interstial fluid as well as intracellular fluid the chief difference between the plasma and the interstitial fluid is that the plasma has a bunch of proteins remember it has all those plasma proteins that help to maintain the blood colloid osmotic pressure and proteins mainly have negative charges the interstitial fluid doesn't have many plasma proteins because plasma proteins generally can't move out of the blood vessels the plasma also has a little bit more sodium but less chloride ions but otherwise they're essentially the same thing if we look at the three compartments and in this case the Red's plasma the Blue's interstitial fluid and the yellow is intracellular fluid um you can see the distribution of the different um different electrolytes okay sodium in the intertial fluid as well as in the plasma very little in the cell on the other hand pottassium is mainly in the cell with very little outside calcium is mainly in the blood it's very low concentration ation overall uh but the lowest is inside cells magnesium is mainly in the cells magnesium is important co-actor in uh different enzymatic reactions chloride chloride pretty much follows sodium around it goes wherever sodium goes so the ratios U are the same even though the proportions are a little bit different you find the most in the interstitial fluid fluid and then slightly less in the blood and then a whole lot less inside the cell bicarbonate um is mostly in the interstitium and the plasma but there's also bicarbonate in the cells phosphat mainly inside the cells think of putting phosphates on um some proteins have phosphates phosphates are major component of nucleic acid so there has to be plenty of phosphates there we have to put phosphate on ATP to make ATP as well as a Denine diphosphate and phosphorilation of proteins is the main way we turn them on and off so the by far the greatest proportion of phosphates are going to be in the cell sulfates um are a component of many proteins uh and proteins that have lots of sulfates tend to have a particular type of bond called the disulfate bond which is really um a disulfide bond which is really strong bond um and then protein anion we have more proteins inside the cell remember proteins tend to have a net negative charge uh we have way more proteins inside the cell than anywhere else but then we have all the plasma proteins so the one place we don't find it very much is in the interum so let's look at some of these electrolytes one by one now we probably haven't talked about anything as much as we've talked about sodium this semester but it's the most abundant extracellular ion it's an ant it's a cat ion meaning has positive charge and it accounts for half of the osmolarity the extracellular fluid so half of the solute that makes up the concentrations of solute is sodium on average our daily intake is going to exceed normal requirements it's controlled mainly by aldosterone um because that causes the reabsorption of it um so that's the major regulator of sodium potassium and aldosterone uh ADH release ceases if their sodium levels are too low uh and the urine's going to be dilute until the sodium levels rise atrial natural tic peptide increases sodium in water excretion if it's too high if you have excess sodium in the body it can result in edema or swelling excess loss of sodium can cause excessive loss of water because where it goes water follows and that results in hypovolemia if you have an abnormally low blood volume you can go into hypovolemic shock and die because the blood won't be able to be pumped to all the cells because the pressure will be too low low so sodium retention causes water retention and edemas abnormal accumulation of interstitial fluid some of the things that can cause sodium retention hyperaldosteronism uh and renal failure if you have too much sodium loss then you could have um hypovolemia that could come from an inadequate secretion of aldosterone or the use of too many diuretics chloride is the major extracellular an ion so sodium is Major extracellular Caton this is the major extracellular an I um it can move easily between the compartments it helps balance the anion in different compartments it's indirectly controlled by aldosterone because where sodium goes chloride wants to go um and Ada also helps to regulate chloride and body fluids because it controls the water loss in urine chloride shift across red blood cells with buffer movement um so it it's going to shift as buffer shift so is the chloride and it also is really important in forming hydrochloric acid in the stomach potassium is the most abundant cat I in the intracellular fluid and it's involved in maintaining fluid volume um impulse conduction muscle contraction ex exchange for hydrogens to help regulate PH in the intracellular fluid uh the plasma level is mainly under the control of aldosterone this is important in resting membrane potential and repolarization um aldosterone stimulates the principal cells to increase potassium secr into the urine and if you have abnormal plas plasmic uh potassium levels it can affect your heart as well as muscle function bicarbonate is the prominent ion in the plasma and it too is an an I like chloride it is uh major component in plasma acidbase buffer system as blood flows through the capillaries the concentration of bicarbonate in increases because of water and CO2 that are being released from cells that are producing ATP it decreases as blood flows through the pulmonary cap capillaries and um carbon dioxide is exhaled and the kidneys are going to be the main Regulators of plasma levels the intercalated cells are going to form more by carbonate if your levels are too low and excrete the excess in urine calcium is the most abundant ion in the body and it's principally extracellular it's a cat ion um it's involved in bones and teeth it's important in blood clotting neurotransmitter release muscle tone nerve and muscle function and it's regulated by the parathyroid hormone it stimul ulates osteoclast to release calcium from bone increases production of calcitriol um which is the active form vitamin D so it increases calcium absorption from the GI tract as well as reabsorption from the filtrate magnesium is primarily intracellular it is a co-actor in a lot of different enzymatic systems it's also needed for operation of the sodium potassium pump it's important in neuromuscular activity neural transmission and myocardial functioning and a number of factors regulate it um they include the hypo or hypercalcemia hypo or hypo mag magnes magnesia she um an increase or decrease in extracellular fluid volume and increase or decrease in par thyroid hormone as well as acidosis and alcohol osis phosphate is pres calcium phosphate in bones and teeth it's in phospholipids ATP DNA RNA it's important intracellular anion and it acts as a buffer of hydrogen ions in body fluid as well as in urine remember if urine gets too acidic phosphate is released to buffer it plasma levels are regulated by the parathyroid hormone as well as calcitriol because as if you break down bone you're going to release not only calcium but phosphate as well um in the kidney parathyroid hormone increases phosphate excretion and calcitriol increases GI absorption phosphate as well as calcium people that are at risk for fluid and electrolyte imbalances include people that are dependent on others for fluid and food needs those like people in nursing homes people with dementia you know Alzheimer's things like that children um those undergoing medical treatment that involves IVs drainage or suction urinary catheters people that have to have diuretics people that are post-operative people who burn victims chronic diseases as well as people with Altered States Of Consciousness the goals for this lecture describe what's meant by electrolyte um name unit generally used to measure electrolytes list the importance and location of the highest concentration of each of the following electrolytes sodium chloride pottassium bicarbonate calcium Magnesium phosphate how does electrolite balance relate to edema and hypovolemia and what types of individuals are most at risk for fluid imbalances