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Chapter 10. Water and the Electrolytes. Water: The Internal Sea. Functions of water in the body Solvent Lubricator Transporter Regulates temp & pH (7.4). Distribution of Body Water. In adults, ~ 60% of total body weight Intracellular fluid: ~2/3 water inside cells
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Chapter 10 Water and the Electrolytes
Water: The Internal Sea • Functions of water in the body • Solvent • Lubricator • Transporter • Regulates temp & pH (7.4)
Distribution of Body Water • In adults, ~ 60% of total body weight • Intracellular fluid: ~2/3 water inside cells • Extracellular fluid: ~1/3 water outside cells 10-9
Movement of Water • Osmosis: movement of water to balance the concentration of solvent 10-10
Water Balance Intake = Output 10-11
Regulation of Water Intake • Signals from the brain (hypothalamus) • Dry mouth motivate the consumption of fluid
Regulation of Water Losses • Antidiuretic hormone (ADH): • acts on kidneys to increase water reabsorption 10-14
Recommended Water Intake • DRI: • Men: 3.7 liter/day • Women: 2.7 liter/day • Activity, heat, humidity, and diet • Pregnancy & lactation needs increased 10-15
Water Deficiency: Dehydration • Adverse effects
Water Toxicity: Overhydration • May occur with illness • Too much plain water is used to replenish lost sweat • Causes electrolyte imbalance
Electrolytes • Electrolytes: mineral salts that dissociate in water to form charged ions • Sodium, Chloride, and Potassium • Functions: • Fluid balance: affects water distribution • Nerve functions • Muscle contractions
Electrolytes in our diet • Processed foods: sodium • Fresh foods: potassium
Regulation of Electrolyte Balance • Sodium: regulates extracellular fluid volume • Potassium: regulates intracellular fluid volume • Homeostasis is regulated by the intake of both water and salt 10-22
Electrolyte Deficiency • Heavy and persistent sweating, chronic diarrhea or vomiting • Deficiencies of any of the electrolytes electrolyte imbalance • Symptoms: poor appetite, muscle cramps, confusion, & irregular heart beat 10-25
Electrolyte Toxicity • Excess salt intake excreted by the kidneys • In salt-sensitive individuals, the regulatory mechanisms are unable to prevent rises in blood pressure as salt intake increases • High risk for hypertension 10-26
Sodium & blood pressure • Water follows salt • Salt intake blood volume increases blood pressure increases • What happens when blood pressure is low?
Hypertension: “The Silent Killer” • Optimal (Systolic): 90-120 mm Hg • High blood pressure: 140/90 mm Hg or higher • What causes hypertension? • Disturbances in the mechanisms that control body fluid and electrolyte balance 10-27
Risk Factors of Hypertension • Genetics: Family history, ethnic & racial background • Age • Conditions: Diabetes, kidney damage, obesity • Lifestyle: Physical activity, heavy alcohol consumption, smoking, stress,
Diet and Blood Pressure • High salt intake • Increases risk in salt sensitive people • Potassium, calcium, & magnesium intake • Lowers incidence of hypertension • What type of diet would you recommend? 10-30
D.A.S.H. • Dietary Approaches to Stop Hypertension • A diet high in fruits &vegetables, low in fat • DASH Trial
Preparing a 1 (one) litre oral rehydration solution [ORS] using Salt, Sugar and Water at HomeMix an oral rehydration solution using one of the following recipes; Ingredients: • one level teaspoon of salt • eight level teaspoons of sugar • one litre of clean drinking or boiled water and then cooled5 cupfuls (each cup about 200 ml.) • Preparation Method: • Stir the mixture till the salt and sugar dissolve.
Objectives • Functions of water • Regulation of water intake & loss • Define and name major electrolytes • Functions of electrolytes • Role of Na in blood pressure • Diet modification for high blood pressure