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Fluids
- -Substances composed of freely moving molecules
- -Have ability to conform to the shape of container
-50-70% of healthy adult is composed of fluids
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Extracellular fluid
- Tissue fluid found between the cells w/in tissues and organs of the body
-Plasma, fluid portion of blood that carries blood cells
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Intracellular fluid
-Fluid within the the body cells
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Composition of body fluid tissues
Tissue type: lean tissues = high fluid content
Gender: males = more lean tissue
Age: lean tissue lost with age
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Electrolytes
Mineral salts dissolved in water, including: sodium, potassium, chloride, phosphorus
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Function of Fluids
- -Blood volume is the amount of fluid in the blood
- -Increased blood volume can cause blood pressure to rise (hypertension)
- -Decreased blood volume can cause low blood pressure
- -Fluids help maintain body temperature
- -Fluids protect and lubricate body tissues
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Functions of Electrolytes
- -Help regulate fluid balance
- -Help nerves respond to stimuli
- -signal our muscles to contract
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Thirst mechanism
Cluster of nerve cells that stimulate our desire to drink
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How is water lost from our bodies?
- Urine
- Sweat
- Exhalation
- Feces
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How is water gained for our bodies?
- Beverages
- Food
- Metabolic reactions
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Functions of water; Recommended intake?
- - Essential for life
- - Required for fluid and electrolyte balance and metabolic reactions
- 1-1.5 ml for each kcal expended
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Too much water vs. Not enough water
Too much: dilution of sodium (hyponatremia)
Too little: dehydration
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Functions of sodium
- - Fluid and electrolyte balance
- - Associated w/ BP and pH balance
- - Required for nerve impulse transmission
- - Transport of nutrients (e.g. glucose) into body cells
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Recommended sodium intake?
- 1.5g/day required
- <2.3g/day recommended
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Too much sodium vs. Not enough sodium
Too much: Hypernatremia, abnormally high blood sodium concentrate; high blood volume, edema, high BP
Too little: Hyponatremia, abnormally low blood sodium level; consume too much water and fail to replace sodium
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Functions of potassium
- - Fluid/electrolyte balance
- - muscle contractions, transmission of nerve impulses
- - lower BP
- - maintain acid-base balance
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Recommended intake of Potassium
4.7g/day
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Too much potassium vs. Not enough potassium
Too much: Hyperkalemia, high blood potassium level; patients w/kidney disease, alter heart rhythm
Too little: Hypokalemia, low blood potassium level; patients w/kidney disease
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Functions of chloride
- - Maintaining fluid balance
- - Assists w/immune system
- - Component of HCl in stomach
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Recommended intake of chloride
2.3g/day
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Too much vs. Not enough chloride
Too much: Lead to hypertension
Too little: Rare, but can occur w/people who have eating disorders
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Functions of Phosphorus
- - Major intracellular negatively charged electrolyte
- - Required for fluid balance
- - Bone formation
- - Regulates biochemical pathways by activating/deactivating enzymes
- - Found in ATP, DNA, RNA
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Recommended intake of Phosphorus
700mg/day
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Too much phosphorus vs. Not enough phosphorus
Too much: too many Vitamin D supplements; causes muscle spasms, convulsions
Too little: Deficiencies are rare
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Dehydration
- Water loss exceeds water intake
- - Due to heavy exercise or high environmental temperatures
- - Infants/elderly more at risk
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Causes of dehydration
- - Diarrhea
- - Vomiting
- - Fever
- - Burns
- - Poorly managed diabetes
- - Abuse of diuretics or laxatives
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Heart cramps
- Painful muscle cramps, in abdomen, arms, or legs
- - develop during vigorous activities
- - spasms last seconds or minutes
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Heat exhaustion
- - Occurs from vigorous activity in heat
- - symptoms include cramps, weakness, vomiting, dizziness, elevated BP/heart rate
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Heatstroke
- Body's temperature regulation mechanisms fail
- - hot, humid environments
- - symptoms include rapid pulse, hot/dry skin, high body temp, weakness
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