Amino acids and proteins

Electrolytes

OutlineIntroductionWaterThe ElectrolytesAnion Gap

IntroductionElectrolytes Ions capable of carrying an electric chargeTwo types of Ions:AnionsIons that carry (-) charge and move toward the anodeE.g. Cl-, HCO3-, PO4-CationsIons that carry (+) charge and move toward the cathodeE.g. Na+, K+, Mg2+, Ca2+

IntroductionFunctions of ElectrolytesVolume and osmotic regulation (Na+, Cl-, K+)Myocardial rhythm and contractility (K+ , Mg2+, Ca2+)Neuromuscular Excitability (K+ , Mg2+, Ca2+)Cofactors in enzyme activation (Mg2+, Ca2+, Zn2+)Regulation of ATPase ion pumps (Mg2+)Acid-base balance (HCO3-, K+, Cl-)Production and use of ATP from glucose (Mg2+, PO4-)

OutlineIntroductionWaterThe ElectrolytesAnion GapElectrolytes and Renal Function

OutlineWaterIntroductionOsmolalityDefinitionClinical Significance of OsmolalityRegulation of Blood VolumeDetermination of OsmolalityWaterIntroduction40% - 75% of body weightFunction:Transport nutrients to the cellsDetermines cell volumeRemoves waste productsAct as bodys coolantLocation:Intracellular Fluid (ICF) 2/3Extracellular Fluid 1/3 Intravascular extracellular fluid and interstitial cell fluid

WaterIntroductionDistribution of Body Water in AdultCompartmentPercent (%) of Body WeightPercent (%) of Total BodyWaterExtracellular Plasma58 Interstitial1525Intracellular4067Total Body Water60100

WaterIntroductionConcentration of ions is maintained by:Passive TransportPassive movement of ions across a membraneActive TransportMechanism that requires energy to move ions across cellular membranesATPase-dependent ion pumps

OutlineWaterIntroductionOsmolalityDefinitionClinical SignificanceRegulation of Blood VolumeDetermination of OsmolalityWaterOsmolalityDefinitionPhysical property of a solution based on concentration of solutes per kilogram of solvent (millimoles/kg)Blood osmolarity is regulated by:Thirst SensationArginine vasopressin hormone (AVP)

WaterOsmolalityClinical SignificanceBlood osmolarity is regulated by:Thirst SensationResponse to consume more fluidsPrevents water deficit or dehydrationArginine vasopressin hormone (AVP)Antidiuretic Hormone (ADH) reabsorption of water in kidneysSuppressed in excess water load ( POSM) Activated in water deficit ( POSM)

WaterOsmolalityRegulation of Blood VolumeRenin-angiotensin-aldosterone system blood volume/pressure Renin (kidneys) Angiotensin I Angiotensin II Vasoconstriction and aldosterone ( Na+ )Other FactorsANP - Na+ excretion in the kidneyAVP - water reabsorption in the kidneyGFR w/ vol. expansion and w/ vol. depletion plasma Na+ will urinary Na+ excretion

WaterOsmolalityRegulation of Blood Volume

WaterOsmolalityDetermination of Osmolality and Osmolal gapSpecimen Serum or urineOsmolality Indicates number of molecules per Kg of solventAny substance dissolve in a solvent will: the freezing point by 1.858C the boiling point by 0.52C vapor pressure (Dew point) by 0.3 mmHg the osmotic pressure by 17,000 mmHgMain contributors are Na, Cl, Urea and Glucose

OutlineWaterIntroductionOsmolalityDefinitionClinical Significance of OsmolalityRegulation of Blood VolumeDetermination of OsmolalityOutlineIntroductionWaterThe ElectrolytesAnion GapElectrolytes and Renal Function

OutlineThe ElectrolytesConcentration of Cations and Anions in Extracellular and Intracellular WaterConcentration of WaterConcentration of WaterCationExtracellular (mmol/LIntracellular (mmol/L)AnionExtracellular (mmol/LIntracellular (mmol/L)Na+136-14515HCO3-23-2910K+3.5-5.1150Cl-98-1071Ca2+2.15-2.51HPO42-0.78-1.4250Mg2+0.63-113.5SO42-0.510

OutlineThe ElectrolytesSodiumPotassiumChlorideBicarbonateMagnesiumCalciumPhosphateLactateThe ElectrolytesSodium (Na+)Description and RegulationClinical ApplicationsDetermination of SodiumThe ElectrolytesSodium (Na+)Description and RegulationThe most abundant cation in the ECF Major Extracellular cationNa+, K+ -ATPase ion pump moves 3 Na+ ions out of the cell in exchange for 2 K+ ions

The ElectrolytesSodium (Na+)Description and RegulationPlasma concentration depends in renal regulationIntake of water in response to thirstExcretion of water as affected by AVP H2O reabsorptionThe blood volume status, which affects Na excretion through:Aldosterone ( Na+ reabsorption in the kidneys)Angiotensin II ( aldosterone)ANP ( Urinary Na + Excretion )

The ElectrolytesSodium (Na+)Description and Regulation

The ElectrolytesSodiumDescription and RegulationClinical ApplicationsDetermination of SodiumThe ElectrolytesSodiumClinical Applications

Sodium (Na+) LossHypoadrenalism ( aldosterone)Potassium (K+) DeficiencyDiuretic Use (Thiazide)Ketonuria (Na+ lost with ketones)Salt-losing nephropathyProlonged vomiting or diarrhea Water RetentionRenal failure (dilution of Na+)Nephrotic s. (COP - PV, AVP)CHF, Hepatic cirrhosisCauses of Hyponatremia ( Na+)Water ImbalanceSIADH ( AVP , H2O retention)Pseudohyponatremia

The ElectrolytesExcess Water LossDiabetes insipidus ( AVP)Renal tubular dis. ( urine conc.)Prolonged diarrhea Profuse sweatingSevere burnsDecreased Water IntakeOld/Infants / Mental ImpairmentCauses of Hypernatremia ( Na+)Increased Intake or RetentionCushing Syn. ( Na+ reabs.)Hyperaldosteronism ( AVP)Hypertonic Salt SolutionSodiumClinical Applications

The ElectrolytesSodiumDescription and RegulationClinical ApplicationsDetermination of SodiumThe ElectrolytesSodium (Na+)Determination of SodiumSpecimenSerum, Plasma (lithium heparin, ammonium heparin and lithium oxalate)False with marked hemolysisMethodsFESAASISE (Glass ion-exchange membrane)

OutlineThe ElectrolytesSodiumPotassiumChlorideBicarbonateMagnesiumCalciumPhosphateLactateThe ElectrolytesPotassium (K+)Description and RegulationClinical ApplicationsDetermination of PotassiumThe ElectrolytesPotassium (K+)Description and RegulationMajor Intracellular cationRegulation of neuromuscular excitability and contraction of heart, ICF volume, H+ conc. K+, cell excitability (muscle weakness) K+, cell excitability (arrhythmia or paralysis)

The ElectrolytesPotassium (K+)Description and RegulationAldosterone K+ excretion in urine in exchange for Na+Na+, K+ -ATPase pump function cellular entry hypoxia, digoxin overdose, hypomagnesemia, propanolol (-blocker) function cellular entry insulin, epinephrine with exercise, hyperosmolality (DM) and cellular breakdown

The ElectrolytesPotassium (K+)Description and Regulation

The ElectrolytesPotassium (K+)Description and RegulationClinical ApplicationsDetermination of PotassiumThe ElectrolytesPotassiumClinical ApplicationsGI LossVomiting, DiarrheaGastric suctionIntestinal tumor, malabsorptionCancer therapy, laxativesRenal LossDiuretics, Nephritis, CHFRTA (H+,K+ excretion)Cushings syn. (Na+,K+ reabs.)HyperaldosteronismHypomagnesemia: aldosteroneCauses of Hypokalemia ( K+)Cellular Shift - K+ uptake Alkalosis (Plasma)-H+Na+K+Insulin Overdose Decreased Intake

The ElectrolytesPotassiumClinical ApplicationsDecreased Renal ExcretionRenal FailureHypoaldesteronism ( Na+)Addisons D.(Na+, K+ reabs)Cellular ShiftAcidosis (Plasma H+, K+)Muscle/cellular injuryChemotherapy / LeukemiaHemolysisCause of Hyperkalemia (K+)ArtifactualHemolysis, ThrombocytosisProlonged tourniquetIncreased IntakeOral/IV - K + replacement therapy

The ElectrolytesPotassium (K+)Description and RegulationClinical ApplicationsDetermination of PotassiumThe ElectrolytesPotassium (K+)Determination of PotassiumSpecimenSerum, Plasma (heparin)False with hemolysis24 hour urineMethodsFESAASISE (Use valinomycin membrane)

OutlineThe ElectrolytesSodiumPotassiumChlorideBicarbonateMagnesiumCalciumPhosphateLactateThe ElectrolytesChlorideDescription and RegulationClinical ApplicationsDetermination of ChlorideThe ElectrolytesChlorideDescription and RegulationMajor Extracellular AnionInvolve in maintaining osmolality blood volume and electric neutrality (Chloride shift)Rate limiting component in Na+ reabsorption

The ElectrolytesChlorideRegulationClinical ApplicationsDetermination of ChlorideThe ElectrolytesChlorideClinical ApplicationsExcess Loss of HCO3-GI LossesRTAMetabolic acidosisCause of Hyperchloremia (Cl-)Excess Loss of Cl-Prolonged VomitingDiabetic KetoacidosisAldosterone DeficiencySalt-losing pyelonephritisCause of Hypochloremia (Cl-)

The ElectrolytesChlorideDetermination of ChlorideSpecimenSerum, Plasma (lithium heparin)False with marked hemolysis (dilution)24 hour urineMethodsISE (Use ion exchange membrane)Amperometric-coulometric (Cotlove Chloridometer)

The ElectrolytesChlorideDetermination of ChlorideMethodsSchales and SchalesTitration with mercuric nitrate Indicator S-diphenylcarbazone

Colorimetric

OutlineThe ElectrolytesSodiumPotassiumChlorideBicarbonateMagnesiumCalciumPhosphateLactateThe ElectrolytesBicarbonate (HCO3-)Regulation and Clinical ApplicationsDetermination of SodiumThe ElectrolytesBicarbonate (HCO3-)Regulation and Clinical Applications2nd Most Abundant anion in the ECFAccounts for more than 80% of total CO2 with HCO3-Major component of the buffering system of the blood

Metabolic AlkalosisSevere vomiting, HypokalemiaHypoventilationExcessive alkali intake HCO3-Metabolic acidosisHyperventilation HCO3-The ElectrolytesBicarbonate (HCO3-)Regulation and Clinical ApplicationsDetermination of SodiumThe ElectrolytesBicarbonate (HCO3-)Determination of SodiumSpecimenSerum, Plasma (heparin)False if left uncapped ( 6mmol/L per hour)MethodsISE (Use of pCO2 electrode)Enzyme method

OutlineThe ElectrolytesSodiumPotassiumChlorideBicarbonateMagnesiumCalciumPhosphateLactate