Chapter 11: Water and Electrolytes Flashcards
Water Body Weight
60% of body weight and dependant on body’s composition
Weight of lean tissues
3/4 of lean tissue is water weight
Weight in fat tissue
less than 1/4 of weight in fat tissue
Proportion of water is lower in
females
people with more adipose tissues
elderly
Functions of water and the body fluids
-Carries nutrients and waste products
- maintains the structure of large molecules
- metabolic reactions
-solvent
- Lubricant
- Body temp Regulation
- Blood volume
Distribution and movement of body fluids
all cells are surrounded by intracellular and extracellular fluid
Osmosis
Water moves in the direction of the more concentration solution
Electrolytes that reside inside the cell
P, K, Mg, S
Some electrolytes reside outside the cell
Na, Cl
Water flows electrolytes across the cell membrane
Osmosis
Proteins act as
water attracters
regulate fluid movement
passage of ions across the cell membrane
sodium potassium pump
Regulation of fluid and electrolyte balance
GI Tract
Kidneys
Water intake
controlled by the hypothalamus
Less water = concentrated water = inc thirst
More water = distention of stomach = decreased thirst
Dehydration
Thirst, weakness, exhaustion, delirium
Water Intoxication
Confusion, convulsions, death, hyponatremia
Water Recommendations
1-1.5 ml/kcal (adults)
1.5 mL/kcal expended (infants and athletes)
AI for total water
Men: 3.7 L/day
Women: 2.7 L/day
Sodium
NaCl, preserves food and enhances taste, controls
-fluid balance
-acid-base balance
-nerve transmission
-muscle contraction
travels freely in the blood to the kidneys
AI for sodium
1500 mg/day (19-50)
1300 mg/day (51-70)
1200 mg/day (70)
CDRR for sodium
2300 mg/day
Chloride
Essential nutrient
fluid and nutrient balance
sodium outside the cell and potassuim inside the cell
moves passively through membrane channels
part of HCl
Deficiency and toxicity are rare
Potassium
Cation found inside cells
fluid and electrolyte balance
nerve transmission and muscle contraction
sodium and potassium trade places and then quickly trade back
Potassiuma nd hypertension
Lower potassium and higher sodium equals higher blood pressure
Potassium Toxicity
Not due to food so no UL has been set
due to certain diseases or medications
Negative water balance
water loss is greater than water consumed
Causes of dehydration
Diarrhea
vomiting
fever or excessive sweating
unmanaged diabetes
diuretic use
