fluid balance chapter 27 Flashcards
what is total body water=
function of age, body mass, sex and amount of body fat
does total body water increase or decrease throughout lifetime
decrease about 45% in elderly
infants total body water is about ?
75%
low body fat
low bone mass
males total body water is about?
60%
more skeletal muscle and less fat
females total body water is about
50%, lower due to higher body fat and smaller skeletal muscle
what is the least hydrated tissue, with a low water content
adipose
what compartment contains
2/3 Volume = 28 L of 40 L TOTAL
ALL Fluid inside Body Cells – Cytoplasm = 70% Body’s H2O
40% of Body total Weight
intracellular
what does the extracellular fluid contain
1/3 volume -12 L of 40 L total
30% body’s H2O
20% od bosy total weight
plasma, IF, other ECF are in IFC or ECF
ECF
what is blood fluid and links internal and external environments
plasma
what is in between cells
IF
what contains lymph, CSF, eye humors, synovial fluid, serious fluid and GI secretions
ECF
term for amount of force applied to solution that prevents solvent from moving across semipermeable membrane
osmotic pressure
term for pressure any fluid in a confined space exerts, due to force of gravity
hydrostatic pressure
what is the movement of solvent from lower concentration of solute to more concentrated
osmosis
what does the total osmotic pressure in each compartment allow
continuous exchange of H2O and electrolytes between compartments
exchange between plasma and IF=
capillary walls
hydrostatic pressure of blood forces plasma out of blood into what?
interstitial space
during hydrostatic pressure it will be reabsorbed into bloodstream in response to what
colloid osmotic pressure of plasma proteins
what picks up IF and returns it into blood
lymph capillaries
exchange between IF and ICF=
plasma membranes
what is the exchange between IF and ICF dependent on
permeability
what has a 2 way osmotic flow of water
exchange between IF and ICF
ions move via what
active transport or via channels
what moves in one direction
nutrients, resp gases, waste move in 1 direction
water balance is what
water intake= water output
why is water balance so important
to maintain hydration
alteration in total water volume has an effect on
body fluid solute concentration, BP, IF pressure
how much water do we intake
2500 ml/day
60% fluids
30% foods
10% cell metabolism
what is insensible and sensible water loss classified as
output
example of insensible output of water
expired air vapor
skin 28%
lung
example of sensible water loss
measurable via urine
perspiration
feces
what is our thirst mechanism
hypothalamus thirst center
what receptors does the hypothalamus thirst center have
osmoreceptors
what do osmoreceptors detect
ECF osmolality via PM stretch changes from gain/ loss of water
what activated the hypothalamus thirst center
change of 1-2%
what does dry mouth signal
blood osmotic pressure increases-> less saliva
decreased BV/ BP does what
triggers thirst by baroreceptors detecting changes in volume or pressure
when does the thirst mechanism become problematic
during athletic activity
elderly/ confused
renal/ CV patients with fluid overload still thirsty
what is from insensible and sensible water loss
need to flush metabolism end products out of body
obligatory water losses
what do the kidneys excrete 30 minutes after ingestion
H2O
there is a delay of fluid otput due to
time needed to inhibit ADH release
when does diuresis peak
1 hour after drinking
when does diuresis decrease the lowest at
3 hours
low ADH=
adequate diluted urine
high ADH=
small amount of concentrated using produced
what other hormones are used in fluid regulation
angiotensin, aldosterone, ANF
what are water balance disorders
dehydration, edema, hypotonic hydration
profuse sweating for xs time, xs EtOH consumption results in
loss
loss exceeds intake over time, creates - fluid balance
dehydration
when does dehydration occur
after hemorrage, severe burns, xs diarrhea, vomiting, profuse sweating, water deprivation, diuretic abuse, DI and DM
what are early signs of dehydration
cottony oral mucosa, thirsty, dry flushed ski and decreased urinary output
what are later signs of dehydratioin
weight loss, fever, mental confusion
hypovolemic shock
what is edema
swelling- atypical accumulation of fluid in interstitial space-> tissue swelling
what is water intoxication
hypotonic hydration
what is hypotonic hydration
overconsumption of water and electrolytes that become xs diluted
when does hypotonic hydration occur
after overexertion in hot conditions
who does hypotonic hydration occur the most in
marathon runners
plain water->
Na+ plasma to drop
in hypotonic hydration you experience sudden and severe what
hyponatremia
if you become unconscious what happens
IVF and hypertonic
you need fluid replacement if what happens
xs vomit and diarrhea
water goes into cells and swells which causes what
increased intracranial pressure
symptoms of hypotonic hydration
severe H/A, confused, nausea, muscle cramps, seziure, coma-> death
how to prevent hypotonic hydration
fluids with electrolytes
treatment for hypotonic hydration
adminster IV hypertonic saline- reverse osmotic gradient/ pul H2O out of cells
