Fluid + Electrolytes Flashcards
fluid accounts for _____% of our body weight. how does intracellular weight % compare to extracellular %?
60% of our weight
20% extracellular
40% intracellular
___% of our body weight is plasma fluid. ____% is interstitial fluid
5% plasma
15% interstitial
t/f: gastrointestinal fluid contributes 2% of our body weight
false… very low amt(
t/f: body has innate mechanism to correct for fluid imbalance
true: conserve or expel
obligatory water loss + quantity
amt of water needed to expel daily nitrogenous wastes, sodium, urea, etc. (aka: urine can only be concentrated so much)
-approx. 500 mL/d
4 ways we lose water
- sweat
- breath(water vapor)
- urine
- feces
how much water is excreted in the breath/d? how much in feces/d?
about 250 mL for a sedentary person in breath
200 mL in feces
3 ways we can take in water
- drinking
- eating water rich foods
- water as a byproduct of normal metabolic rxns
rank the macronutrients in terms of catabolic water derivatives
CHO (15 mL/100 kcal), fat (11 mL/100 kcal), protein (10 mL/100 kcal)
up to _____% of daily water intake can be derived from foods, depending on foods chosen
20
why does water not have an RDA and only an AI? (3 reasons)
because it’s too highly variable to have a recommendation for everyone. varies based on body size, ambient temp, and physical activity
t/f: hydration status can easily be tested
false! no one good test…
t/f: even very dry foods like peanuts have water contents
true!
4 biomarkers of hydration status
- blood
- urine volume
- urine color
- thirst
what is the caveat to testing hydration status?
must look at several biomarkers because other conditions (other than dehydration) can cause abnormally low of one biomarker
what two things are tested in the blood to determine hydration status
[Na], [BUN]
what could cause elevated levels of BUN and plasma sodium besides dehydration
kidney failure(cannot excrete materials well)
where does BUN come from?
deamination of AA…
what can cause a normal [BUN] even if someone is dehydrated?
BUN comes from deamination of proteins, so if the ind. eats a low protein diet, they will not have an elevated [BUN] in time of dehydration
t/f: the kidneys continue to filter, even if we are severely dehydrated
true!`
what is the normal and dehydrated ranges for urine volume?
normal= 100 mL/hr
dehydrated=
low urinary volume can also be caused by what disorder in addition to dehydration?
kidney failure
what are 3 things that can darken urine besides a dehydrated state?
antibiotics, supplements, some foods
what is the best way to determine if a patient is drinking enough?
ASK them how much they’ve drunken in the past 24 hr!
negative water balance is detected two ways in the body… what are these receptors and what do they sense?
osmoreceptors: sense increased plasma osmolarity
baroreceptors: sense decreased plasma volume