bodily fluids Flashcards
how much of the body weight is ECF?
33%
what is the barrier between intra and extra cellular fluids?
cell membranes
function of capillaries in body fuilds?
form barrier between plasma and tissues
more permeable that cell membranes
how does water reach intracellular fluids?
comes into system throgh drinking, absorbed into blood plasma
capillary membrane permeable to water to cross to bate cels in interstiital fluid
water now reaches the intracellular membrane
output for water?
kidneys urination lungs faeces sweat skin
what is insensible loss?
uncounsous loss of water such as that evaporated from the skin or lungs that we cannot control
what does more fat mean about water levels
less water
what are the functions of water?
primary substrate temp regulator protective cushion: amniotic fluid, CSF lubricant: synovial fluid reactant solvent transport
why is the charged dipole is water so important?
it can disrupt ionic bonds to disolve electrolyes and other things and form shells of hydraton
why is the ability of water to fomr hydrogen bonds special?
this gives it a high boiling point, high specific heat and latent heat of evaporation
also gives high surface tenson
what does the high heat capacity of water mean?
it can absorb and release large amounts of water without a large change in temperature
it can hold heat
what are electrolytes?
charged ions disolved in the water
what is the key difference between the plasma and intesitial fluid?
protein concentration in plasma hold water in vessel
why are interstitia and intracellular fluids iso-osmotic?
total osmolarity is equal and balanced despite different compositions
will the ionic charge be balanced within a fluid compartment?
yes
this will always happen despite different numbers of ions
which ions is the main extrcellular ion?
sodium
what are the functions of sodium ?
contributes to major osmotic pressure of ECF
concentration gradient across cell membrane provides potetial to transport other substances
carriers inward curretn for membrane excitation
main intracellular cation?
potassium
functions of potassium
contributes to osmotic pressure of cytoplasm
calcium functions in body fluids?
low conc in cells
regulates muscle contractions
regulates enzyme activity
regulates exocytosis
functions of magnesium in body fluids?
antagonist of calcum
acts ascofactor for many enzymes
functions of bicarbonate
bufferes hydogen ion concentration
functions of chloride?
counterion for cations and positively charged groups of proteins
whats an anion?
negatively charged ion
whats at cation?
positively charged
main functions of electrolytes
cofactors action potential generation neurotransmitter muscle contractin acide base balance primary and secondary active transport osmosis
what is primary active transport?
drectly uses ATP against a concetration gradient
Na/K pump
what is secondary active transport?
uses indirect ATP to set up a concentration gradient
sodium glucose co-transporter
how does the sodium glucose co-transporter work>
low intracellular Na conc maintained by Na/K pump
Na entry drags glucose too against cncentration gradient
passive system but coupled with Na/K pump to work
what is ficks law
of diffusion
rate of diffusion controlled by the gradient and the distance moved
driving force of diffusion is concentration gradient of solute
diffusion co-efficient varies with:
temperature solvent interactions between solute and solvent size and shape of molecule charge molecue has
what does osmosis require?
semi-pereable membrane
concentration gradient
deifne osmotic pressure
the amount of pressue that needs to be applied to stop the movement of water
what describes osmotic pressure?
Van’t Hoff’s law
what does Van’t Hoff’s law say?
describes that substances in dilute solution obey the ideal gas laws, resulting to the osmotic pressure formula
what is concentration measured in?
molarity
what is molarity?
concentration per litre
difference between molarity and osmolarity?
molarity if amount of stuff
osmolarity if concentration of stuff
work out osmolarity of electrolyte?
osmolar concentraton multiplies by the number of ions in the solution
units for osmolarity?
osm/L
what creates osmotic pressure
plasma proteins
prevent leakage from vessels
what is tonicity?
measure of effective osmolarity
isotonic meaning
two solutions with equal amounts of water molecules on either side of the membrane
hypertonic
one solution more solute
hypotonic
one solution contains less solute
what happens to RCB if the solution they are put in isnt isotonic?
is hypo: cells swell, water moves in
if hyper: cell shrinks, water moves out
why is the tonicity key ?
important to consider if using a saline drip as the drip must be the same toncitiy as the plasma
when is an isotonic IV soltuion used?
concentratin like blood
expand blood vols after loss
saline drip
when is a hypotonic solution used?
concentration less that blood
used for dehydration to push more blood into ces
major extracelllar cation
major extracellular anion
cation: sodium
anion: chlorid
major intacellular cation
potassium
major intracellular anions
phosphates and proteins
what is the solvent of the body?
water
what are the solutes of the body?
disolved substances
