week 8 water and electrolytes Flashcards
What percentage of a person’s body weight is made up of water?
~60%
What is considered the most indispensable nutrient?
Water
What percentage of lean tissue weight is comprised of water?
75%
What percentage of fat weight is comprised of water?
25%
Where is water found in the body?
- Blood vessels
- Cells
- Tissues
- Organs
What is the role of water as a transport vehicle in the body?
Brings nutrients to the cells
What function does water serve as a cleansing agent?
Carries and removes waste products from cells
How does water participate in metabolic reactions?
Acts as a solvent for minerals, vitamins, amino acids, glucose, etc.
What role does water play in joint function?
Acts as lubricant and cushion
What is intracellular fluid?
Water inside cells
What is extracellular fluid?
Water outside cells
What is interstitial fluid?
Fluid between the cells
What is intravascular fluid?
Fluid inside blood vessels
What regulates water intake in the body?
The brain - hypothalamus
What is the primary source of water intake?
- Ingested liquids ~70%
- Ingested foods ~20%
- Metabolic water ~10%
What is the average daily water output?
2.5 L
What is dehydration?
Insufficient water in the body
What are common signs of dehydration?
- Thirst
- Weakness
- Headache
- Exhaustion
- Delirium
What is water intoxication?
Water content too high from excessive ingestion of plain water
What is hyponatremia?
Decreased concentration of sodium in the blood
What should fluid intake be limited to during heavy sweating?
1-1.5 L of water
What are the water recommendations for men?
3.7 litres of fluid from water, beverages, and foods (AI)
What are the water recommendations for women?
2.7 litres of fluid from water, beverages, and foods (AI)
What factors increase water needs?
- Alcohol consumption
- Hot/cold weather
- Diabetes
- Exercise
- Pregnancy
- Fever
What is hard water?
High concentrations of calcium and magnesium
What is soft water?
High concentrations of sodium or potassium
What is the Renin-Angiotensin-Aldosterone System (RAAS)?
System that regulates blood volume and blood pressure
What does aldosterone signal the kidneys to do?
Excrete potassium and retain sodium (and water)
What is the role of antidiuretic hormone (ADH)?
Stimulates kidneys to reabsorb more water and excrete less
What are electrolytes?
Minerals that help maintain fluid balance and carry electrical current
What is osmosis?
Movement of water across a membrane towards concentrated solutes
What can cause fluid and electrolyte imbalance?
- Vomiting
- Diarrhea
- Excessive sweating
- Kidney disease
What is Oral Rehydration Therapy (ORT)?
Treatment for dehydration caused by severe diarrhea
What are major minerals?
Essential mineral nutrients found in amounts larger than 5g in the human body
What are trace minerals?
Mineral nutrients found in amounts less than 5g in the human body
What is the chief ion outside of cells?
Sodium (Na+)
What is the AI for sodium for individuals aged 19-50?
1500 mg/d
What is the AI for chloride for individuals aged 19-50?
2300 mg/day
What is the principal positively charged ion inside body cells?
Potassium (K+)
What is the RDA for phosphorus?
700 mg/day
What are common food sources of phosphorus?
- Animal protein
- Cottage cheese
- Salmon
- Milk
- Beef
What can excess phosphorus lead to?
Calcification of kidneys
what regulates water excretion?
brain and kidneys
what ways is water excreted?
sweat - 30%
urine- 35-50%
breath - 1.5 %
feces- 7%
what is obligatory water excretion?
minimum to excrete waste is 500 ml (2 cups) each day
what is dehydration regulated by?
hypothalamus
if blood pressure falls what is released?
- renin
- angiotensin
- aldosterone
- antidiuretic hormone (ADH)
what is renin?
enzyme released by the kidney cells when blood presure is too low. causes sodium to be reabsorbed and water to be retained
what is needed to maintain fluid and electrolyte balance
- body needs to maintain 2/3 of the body’s fluids being isnide the cells and 1/3 being outside the cells
what is osmotic pressure?
amount of pressure needed to prevent movement of water across a membrane
what is the AI potassium reccomendation for women and men?
2600mg/day women
3400mg/day men
what is the UL for phosphorus?
4000mg/day
