Lecture 11 - Water and Electrolytes Flashcards
Who has the most water in the body?
Children 65%
Adults 60%
Seniors 55%
Where does most water reside in the body?
3/4 lean tissue
< 1/4 fat tissue
What groups have the smallest portion of water?
Females
Obese individuals
Elderly
Why do females have less water than males?
Females have more fat around the hips and thighs. Fat carries less water. Males typically have less fat and more lean muscle which has higher water content
What are some of waters body functions?
- Carries nutrient and waste
- Maintains structures of large molecules
- Metabolic reactions
- Solvent
- Lubricant
- Temp regulation
- Maintains blood volume
What is the difference between Extracellular fluid, intracellular fluid and interstitial fluid?
Extra: outs of the cell (including inter)
Inter: between cells
Intra: within cell
What is the AI for men and women for total water?
Men: 3.7L/day
Women: 2.7L/day
-both include food and liquids
What controls water intake?
The hypothalamus
- recognizes concentrated blood and signals thirst
- recognizes distention of stomach and decreases thirst
What is the first and second signs of dehydration?
1- Thirst
2-Weaknes, exhaustion, delirium
What are the symptoms of water intoxication?
Confusion, convulsions, death
Hyponatremia
What is hyponatremia?
Low Na levels in the blood
What happens when cells are thirsty?
Water from the blood goes to the cells, concentrating the blood. This also constricts blood vessels everywhere, when this happens around the mouth no saliva is produced
Where do we lose water from and in what order in terms of L?
Kidneys
Skin
Lungs
GI
What is the amount of water we have to lose and why?
500ml has to be lost for waste excretion
What is insensible water loss?
Water we don’t think of losing
-from skin and lungs
What is the difference between hard and soft water?
Hard –> Higher in Ca
Soft–> Higher in Na
What are some health effects of water?
Meet body fluid needs
Protect against urinary stones and constipation
What is the fluid balance of cells?
2/3 fluid inside the cell
1/3 outside
How do you control the movement of water?
Cant control the movement of water but we use electrolytes to control the water movement
-electrolytes attract water
What are the 3 Kidney hormones?
Antidiuretic hormone
Renin
Angiotensen
What does ADH do?
Prevents you from losing water, stimulates kidneys reabsorption of water
What does renin do?
Tells kidneys to bring back Na into the body
What does angiotensin do?
Constricts blood vessels
What us used in the kidneys and GI to regulate electrolyte balance?
The Na/K pump
- 3 Na out
- 2 K in
What causes fluid and electrolyte imbalances?
- Prolonged vomiting or diarrhea
- Heavy sweating
- Burns and traumatic wounds
- Meds
How does water regulate the acid-base balance int he body?
Helps to maintain the # of H+ ions
-kidneys and lungs do this too
What is a normal pH range?
7.35-7.45
What common form of Na do we consume?
Sodium Chloride (NaCl) -used to preserve and enhance taste. *but not always in the form of NaCla
Which is worse, Na or salt?
Salt is worse in terms of the side effects
What is Sodium used for?
Fluid balance
Acid base balance
Nerve transmission
Muscle Contraction
What is the UL for Na meant for?
To protect against high blood pressure because we are rarely lacking in Na in our diet
What is salt sensitivity?
After consuming Na, the blood pressure increases but then goes down. A sensitivity would take longer for the BP to go down
How many people will develop hypertension from consuming too much Na?
Only 5%
-most likely to be men because they consume more on average and therefore consume more Na
What is one diet that can prevent hypertension?
DASH Diet
- dietary approaches to stop hypertension
- basically Canadas food guide, emphasizing high fruit and veggie, whole grains low fat
Where is most of the Na in food found?
75% Processed
10% occurring naturally within foods
15% Na we use at the table
Can you be deficient in Na?
You can but it is rare
-Symptoms: Vomiting, heavy sweating, diarrhea, hyponatremia
Can you get Na toxicity?
Short term Na toxicity: deem
Long term: possibility of hypertension
What is Cl involved in?
Helps with a lot of things Na does
- fluid and electrolyte balance
- moves passively through membrane
Where can you find Cl
In a lot of foods, sometimes consumed as a part of salt
Can you get Cl toxicity or become deficient?
Both are rare
-deficiency can happen with extended vomiting
What is K involved in?
Same functions as Na
- fluid and electrolyte balance
- nerve transmission and muscle contraction
What is the trade off between Na and K?
We need more K in our diet than Na but we usually consume more Na than K because they are found together in most foods but in processed foods there is more Na than K
What is hypertension?
Low K + High Na = High Blood pressure
Can you get K toxicity or be deficient?
Both are rare
-Toxicity due to meds or diseases but not from not getting enough
Where do you find most P?
85% in bones, a little but inside the cell
What form does P appear in the body?
Phosphate (PO4 3-)
Roles of P?
- Starts and stops enzymes
- Part of DNA and RNA
- Part of bilayer
- ATP
What foods are P in?
Foods that have protein, it will most likely have P as well
What are the 3 kinds of heat illnesses?
Heat Cramp
Heat Exhaustion
Heat Stroke
What is the second most abundant electrolyte in the body?
Phosphorus
