FLUID BALANCE
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D. C. MIKULECKY FLUID BALANCE
description
FLUID BALANCE. D. C. Mikulecky. FLUID BALANCE. The Balance Concept: Input -Output = Storage/Depletion Body Fluid Compartments Regulation of fluid balance Relation between Salt Balance and ECF Volume. The Balance Concept: Input -Output = Storage/Depletion. Storage. Internal Pool (ECF - PowerPoint PPT Presentation
Transcript of FLUID BALANCE
D. C. MIKULECKY
FLUID BALANCE
FLUID BALANCE
The Balance Concept: Input -Output = Storage/Depletion
Body Fluid CompartmentsRegulation of fluid balanceRelation between Salt Balance and ECF
Volume
The Balance Concept: Input -Output = Storage/Depletion
InternalPool (ECFConcentration) of substance
Storage
MetabolicProduction
MetabolicConsumption
InsideBody
Inputs from environment
Excretion
Body Fluid Compartments
Compartment Fluid Vol.(l)
% BodyFluid
% BodyWgt.
Total BodyFluid
42 100 60
IntracellularFluid(ICF)
28 67 40
ExtracellularFluid (ECF)
14 33 20
Plasma 2.8 6.6(20% ECF)
4
InterstitialFluid
11.2 26.4(80% ECF)
16
Lymph &TranscellularFluid
Neg. Neg. Neg.
BODY FLUID COMPARTMENT COMPOSITION
Plasma InterstitialFluid
IntracellularFluid
Regulation of fluid balance
ECF Volume: Maintains blood pressure
ECF Osmolarity: Prevents swelling or shrinking of cells
ECF Volume: Maintains blood pressure - Short Term
A Change in ECF Volume can raise or lower blood pressure
Barorecepter reflexes: Alter Cardiac output and Total Peripheral Resistance leading to a compensatory alteration in blood pressure
Fluid automatically shifts between plasma and interstitial fluid with rises or fall in blood pressure
Relation between Salt Balance and ECF Volume
The total sodium load (quantity of sodium, not its concentration) in the ECF determines the total amount of water that will be osmotically retained
The total sodium load is determined by the balance relation
The Balance Concept: Input -Output = Storage/Depletion
InternalPool (ECFConcentration) of substance
Storage
MetabolicProduction
MetabolicConsumption
InsideBody
Inputs from environment
Excretion
Control of sodium load
Control of amount filtered by regulating GFR (Glomerular Filtration Rate)
Control of sodium reabsorption through the Renin-Angiotensin-Aldosterone system
ECF Osmolarity: Prevents swelling or shrinking of cells
ECF hypertonicity is associated with dehydration
ECF hypotonicity is associated with overhydration
Control of water balance is by thirst and vasopressin
Blood pressure and renal handling of sodium
FALL IN SODIUM LOAD
FALL IN ARTERIAL PRESSURE
FALL IN GFR
FALL IN FILTEREDSODIUM
INCREASE INALDOSTERONESECRETION
INCREASE IN SODIUMABSORPTION
FALL IN EXCRETION OF SODIUM, CHLORIDE, AND
FLUID
INCREASED CONSERVATIONOF SODIUM AND FLUID
RELIEVES
DAILY WATER BALANCE (LITERS)
FLUID INTAKE 1.25
IN FOOD 1.0
METABOLIC 0.35
INSENSIBLE 0.9
SWEAT 0.1
FECES 0.1
URINE 1.5TOTAL 2.6
INPUT (ml/day) OUTPUT (ml/day)
TOTAL 2.6
WATER DEFICIT
INCREASED OSMOLARITY SENSED BY HYPOTHALAMIC WATER RECEPTORS FALL IN ECF VOLUME
FALL IN ARTERIAL BLOOD PRESSURE
STIMULATIONOF HYPOYHALAMIC NEURONS
INCREASED THIRST
INCREASED WATER INTAKE
DECREASED PLASMA OSMOLARITY
INCREASED VASOPRESSIN
OPEN PORESIN COLLECTINGDUCT
MORE WATER REABSORBED
FALL IN URINE OUTPUT
ARTERIOLARVASOCONSTRICTION
DECREASED PLASMA OSMOLARITY
RELIEVES
RELIEVES
