fluid, electrolyte, and acid-base balance chapter 26

Fluid, Electrolyte, and Fluid, Electrolyte, and Acid-Base BalanceAcid-Base Balance

Chapter 26Chapter 26

Body Water ContentBody Water Content

Varies with weight, age, and sex:Varies with weight, age, and sex: Early embryo (97%)Early embryo (97%) Newborn (77%)Newborn (77%) Adult male (60%)Adult male (60%) Adult female (54%)Adult female (54%) Elderly (45%)Elderly (45%)

Adipose tissue versus skeletal Adipose tissue versus skeletal muscle largely determines adult muscle largely determines adult differences.differences.

Body Fluids and CompartmentsBody Fluids and Compartments

Composition of Body FluidsComposition of Body Fluids

ElectrolytesElectrolytes CationsCations: sodium, potassium, hydrogen, : sodium, potassium, hydrogen,

magnesium, and calciummagnesium, and calcium AnionsAnions: chloride, bicarbonate, phosphate, and : chloride, bicarbonate, phosphate, and

sulfatesulfate

Non-electrolytesNon-electrolytes GlucoseGlucose UreaUrea ProteinProtein LipidsLipids CreatinineCreatinine

Comparison of CompartmentsComparison of Compartments

Fluid Movement Between Fluid Movement Between CompartmentsCompartments

Fluid MovementsFluid Movements

Exchange between blood and interstitial spacesExchange between blood and interstitial spaces

Fluid MovementsFluid Movements

Exchange between extracellular fluids and cellsExchange between extracellular fluids and cells

WaterWater BalanceBalance

Regulation of Water IntakeRegulation of Water Intake

Regulation of Water OutputRegulation of Water Output

Regulation of Water OutputRegulation of Water Output

Obligatory Water LossesObligatory Water Losses Skin and lungsSkin and lungs Urine and fecesUrine and feces

Fluid intakeFluid intake

DietDiet

Levels of Anti-diuretic hormone (ADH)Levels of Anti-diuretic hormone (ADH)

Disturbances in Water BalanceDisturbances in Water Balance

DehydrationDehydration

Hypotonic Hypotonic hydrationhydration

EdemaEdema

Electrolyte BalanceElectrolyte Balance

Regulation of Sodium BalanceRegulation of Sodium Balance

Regulation of Potassium BalanceRegulation of Potassium Balance

Regulation of Calcium and Phosphate Regulation of Calcium and Phosphate BalanceBalance

Regulation of Magnesium BalanceRegulation of Magnesium Balance

Regulation of AnionsRegulation of Anions

Regulation of SodiumRegulation of SodiumBy AldosteroneBy Aldosterone

Regulation of Sodium By ANPRegulation of Sodium By ANP

Regulation of SodiumRegulation of SodiumBy BaroreceptorsBy Baroreceptors

Regulation of SodiumRegulation of Sodium

AldosteroneAldosterone ANPANP BaroreceptorsBaroreceptors Other hormones: Other hormones:

Estrogen=enhances Na+ reabsorptionEstrogen=enhances Na+ reabsorption Progesterone=decreases Na+ reabsorptionProgesterone=decreases Na+ reabsorption Glucocorticoids=enhances Na+ Glucocorticoids=enhances Na+

reabsorptionreabsorption

Regulation of PotassiumRegulation of Potassium

The regulatory site of potassium is in The regulatory site of potassium is in the renal tubulesthe renal tubules

Influence of aldosteroneInfluence of aldosterone

Influence of plasma potassium Influence of plasma potassium concentrationsconcentrations

Regulation of CalciumRegulation of Calcium

Influence of Influence of Parathyroid Parathyroid HormoneHormone

Influence of Influence of CalcitoninCalcitonin

Regulation of PhosphateRegulation of Phosphate

Influence of Parathyroid HormoneInfluence of Parathyroid Hormone Decreases plasma phosphate concentrations Decreases plasma phosphate concentrations

while increasing calcium concentrationswhile increasing calcium concentrations

Influence of CalcitoninInfluence of Calcitonin Increases plasma phosphate concentration Increases plasma phosphate concentration

while decreasing calcium concentrationswhile decreasing calcium concentrations

Regulation of Magnesium Balance Regulation of Magnesium Balance and Anionsand Anions

MagnesiumMagnesium PTH increases plasma magnesium PTH increases plasma magnesium

concentrations by causing a decrease in concentrations by causing a decrease in the amount of magnesium excreted by the the amount of magnesium excreted by the kidneyskidneys

AnionsAnions Chloride is Chloride is indirectlyindirectly increased by increased by

Aldosterone because it passively follows Aldosterone because it passively follows sodiumsodium

Acid-Base BalancesAcid-Base Balances

Strong Acids versus Weak AcidsStrong Acids versus Weak Acids

Chemical BuffersChemical BuffersThree Types:Three Types:

Bicarbonate BuffersBicarbonate Buffers

Phosphate BuffersPhosphate Buffers

Protein BuffersProtein Buffers

Bicarbonate BuffersBicarbonate Buffers

Major extracellular buffering systemMajor extracellular buffering system

HCOHCO33-- functions as a weak base while functions as a weak base while

HH22COCO33 functions as a weak acid. functions as a weak acid.

Example:Example:HCl + NaHCOHCl + NaHCO33- - HH22COCO33 + NaCl + NaCl

Phosphate BuffersPhosphate Buffers

Important in urine and intracellular Important in urine and intracellular buffering systemsbuffering systems

However NaHHowever NaH22POPO44 acts as the weak acid acts as the weak acid and Naand Na22HPOHPO44 serves as the weak base. serves as the weak base.

Example:Example:HCl + NaHCl + Na22HPOHPO44 NaHNaH22POPO44 + NaCl + NaCl

Protein BuffersProtein Buffers

Most abundant buffering system in Most abundant buffering system in the body including intracellular and the body including intracellular and extracellular compartments.extracellular compartments.

Carboxyl groups (COOH) and amine Carboxyl groups (COOH) and amine groups (NHgroups (NH33) act as either an acid or ) act as either an acid or a base respectively.a base respectively.

Physiological BuffersPhysiological Buffers

Two Types:Two Types:

Respiratory Buffering SystemRespiratory Buffering System

Renal Buffering SystemRenal Buffering System

Respiratory Regulation of HRespiratory Regulation of H++

Rising plasma HRising plasma H++ causes deeper, rapid breathing which causes deeper, rapid breathing which decreases COdecreases CO2 2 blood thereby decreasing Hblood thereby decreasing H++ ions. ions.

Renal Buffering SystemRenal Buffering System

Reabsorption of HCO3- is coupled to H+

secretion

Abnormalities in Abnormalities in Acid-Base BalanceAcid-Base Balance

Respiratory acidosisRespiratory acidosis Increased COIncreased CO22=increased H=increased H++=decreased pH=decreased pH Cause: HypoventilationCause: Hypoventilation To compensate: Kidney function=increase To compensate: Kidney function=increase

excretion of H+ or by increased reabsorption of excretion of H+ or by increased reabsorption of HCOHCO33--

Respiratory alkalosisRespiratory alkalosis Decreased CODecreased CO22=decreased H=decreased H++=increased pH=increased pH Cause: HyperventilationCause: Hyperventilation To compensate: Kidney function=decreased H+ To compensate: Kidney function=decreased H+

excretion or by decreased reabsorption of HCOexcretion or by decreased reabsorption of HCO33--

Abnormalities in Abnormalities in Acid-Base BalanceAcid-Base Balance

Metabolic acidosisMetabolic acidosis Decreased HCODecreased HCO33

--=increased H=increased H++=decreased pH=decreased pH Cause: Diarrhea, ketosis, renal dysfunctionCause: Diarrhea, ketosis, renal dysfunction To compensate: Hyperventilation and kidney functionTo compensate: Hyperventilation and kidney function

Metabolic alkalosisMetabolic alkalosis Increased HCOIncreased HCO33

--=decreased H=decreased H++=increased pH=increased pH Cause: Vomiting, diuretics, alkaline drug useCause: Vomiting, diuretics, alkaline drug use To compensate: Hypoventilation and kidney functionTo compensate: Hypoventilation and kidney function

Causes and Consequences of Causes and Consequences of Acid-Base ImbalancesAcid-Base Imbalances

Causes and Consequences of Causes and Consequences of Acid-Base ImbalancesAcid-Base Imbalances

Homeostatic ImbalancesHomeostatic Imbalances

HypernatremiaHypernatremia HyponatremiaHyponatremia HyperkalemiaHyperkalemia HypokalemiaHypokalemia HyperphosphatemiHyperphosphatemi

aa HypophosphatemiaHypophosphatemia HyperchloremiaHyperchloremia

HypochloremiaHypochloremia HypercalcemiaHypercalcemia HypocalcemiaHypocalcemia HypermagnesemiaHypermagnesemia HypomagnesemiaHypomagnesemia HyperproteinemiaHyperproteinemia HypoproteinemiaHypoproteinemia

Homeostatic ImbalancesHomeostatic Imbalances

Homeostatic ImbalancesHomeostatic Imbalances

END TEST IV END TEST IV MATERIALMATERIAL