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Fluids and Electrolytes. Water is the largest single component of the body. Water comprises 95% of the body’s fluids. Water content varies. Infant = 70% water Males = 60% water Females = 50% water Elderly = 45% water Muscle = 65% water Fat = 20% water.
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Fluids and Electrolytes Water is the largest single component of the body. Water comprises 95% of the body’s fluids.
Water content varies • Infant = 70% water • Males = 60% water • Females = 50% water • Elderly = 45% water • Muscle = 65% water • Fat = 20% water
Intake equals Output • Intake (2500ml) • preformed ingested water (60,30) • metabolic water (10) • Output (2500ml) • urine, feces • sweat, evaporation • Regulated by aldosterone and ADH
Water Compartments • Intracellular compartments • 2/3 of total water volume • Extracellular compartments • 1/3 of water volume • Movement between regions by filtration and osmosis
Electrolytes • Acids, Bases and Salts • Substances that dissolve in water, conduct electricity and dissociate into ions
Acid-Bases Balance • pH = - log [H+] • pH = 7.0 is neutral • Normal range is 7.35-7.45 • Control mechanisms • Kidneys • Respiratory System • Buffers
Buffers • Carbonic Acid/Bicarbonate system major regulator of extracellular pH • HCO3- functions as weak base • H2CO3 functions as weak acid • Work by converting a strong acid/base to a weaker one
Phosphate Buffer System • Similar to that of the bicarbonate system • Important urine and intracellular buffer • Component parts: • NaH2PO4 acts as a weak acid • Na2HPO4 acts as a weak base
Protein Buffer System • Most abundant buffering system in the body including intracellular and extracellular compartments • Carboxyl groups (COOH) and amine groups (NH3) act as either an acid or a base
Acid - Base Imbalance Acidosis (pH<7.35) Alkalosis (pH>7.45)
Respiratory Acidosis or Alkalosis • Results from an imbalance of CO2 • Respiratory Acidosis - due to increase of CO2 • decreased respiration results in CO2 H+ pH • Respiratory Alkalosis - decrease of CO2 • increased respiration or hyperventilation CO2 H+ pH • CO2 + H2O H2CO3 H++ HCO3-
Metabolic Acidosis or Alkalosis • Results from imbalance of HCO3- • Metabolic acidosis - due to decrease of HCO3, , which lowers pH • excessive alcohol, prolonged diarrhea, renal dysfunction • Metabolic alkalosis - due to increase of HCO3, which increases pH • excessive vomiting