Physiology - Body Fluid Compartments Flashcards
what is osmolarity?
the concentration of osmotically active particles in a solution
mosmol/l
how do you calculate osmolarity?
molar concentration of a solution x the number of osmotically active particles in the solution
what are the units of osmolality?
osmol/kg of water
what is the osmolarity of body fluids?
around 300 mosmol/l
what is tonicity?
the effect a solution has on cell volume
what are the three tonicities a solution can have?
hypotonic
hypertonic
isotonic
what does hypotonic mean?
causes the cell to swell
what does hypertonic mean?
causes the cell to shrink
what does isotonic mean?
has no effect on cell volume
what two compartments make up TBW?
ICF (66%)
ECF (33%)
what is ECF made of?
plasma
interstitial fluid
lymph
transcellular fluid
how can body fluid compartments volumes be measured?
using tracers
obtain their volume of distribution
what tracer is used to measure TBW volume?
3H2O
what tracer is used to measure ECF volume?
inulin
what tracer is used to measure plasma volume?
labelled albumin