Water and Body Fluids Balance Osmolarity

Electrolytes and ions balance through water

1. Water & The Body Fluids
•60% of adult body weight
-Water makes up ¾ of the
weight of lean tissue
-Water makes up ¼ of the
weight of fat
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2. Water & Body Fluids
•Functions of water:
–Transport
–Structural support for molecules
–Participates in metabolic reactions
–Solvent
–Lubricant & shock absorber
–Body temperature regulation
–Maintains blood volume & blood
pressure

3. Water & The Body Fluids
•Water balance
–Intracellular fluid-within the cells
–Extracellular fluid-outside the cells
•Interstitial fluid
•Plasma
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4. One Cell
And Its
Associated
Fluids
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5. Water & Body Fluids
•Water Balance
-Intake/output = 2.5 liters/day
-Regulated by hypothalamus & kidneys
-Carefully controlled by:
1. Intake (liquid, foods, metabolic water)
affected by thirst & satiety
2. Output (losses via kidneys, skin, lungs,
feces) affected by blood salts, volume &
blood pressure

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How The Body Regulates BloodVolume

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9. Water & Body Fluids
•Recommendations:
-Needs vary according to type of food
eaten, temperature, humidity, activity
level, etc.
-General rule: 1–1.5 ml/kcal expended
Example: if 2000 kcal “burned” then
2-3 liters suggested; >8 cups from fluids
and the rest comes from food &
metabolic water
-Urine should be pale yellow
-Caffeine & alcohol act as diuretics so not
good water substitutes

11. Fluid & Electrolyte Balance
•Electrolytes –salts that dissolve in
water, forming ions
•Dissociation of salt in water
–Ions
•Cations-+ charged particles
•Anions--charged particles
–Electrolyte solution
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Water Dissolves Salts
And Follows Electrolytes

13. Fluid & Electrolyte Balance
•Electrolytes attract water -affects fluid
distribution in the body by osmosis
•Water follows electrolytes
–Solutes
–Osmosis
–Osmotic pressure
•Electrolyte concentration regulated by
kidneys
•Electrolytes & proteins act as buffers to
maintain the pH of body fluids –acid/base
balance
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16. Acid-Base Balance
•pH
•Regulation by the buffers
–Bicarbonate
–Carbonic acid
•Regulation by the kidneys
•Regulation by the lungs
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18. Fluid & Electrolyte Imbalance
•Replacing lost
fluids and
electrolytes
–Oral rehydration
therapy (ORT)-
a simple
solution of
sugar, salt and
water
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19. Fluid & Electrolyte Imbalance
•Sodium and chloride most easily lost
•Different solutes lost by different
routes
•Rapid fluid/electrolyte loss, i.e.
vomiting, diarrhea, heavy sweating,
fever, burns, wounds = medical
emergency
Copyright 2005 Wadsworth Group, a division of Thomson Learning