Fluid balance Flashcards
What is osmolarity?
Conc of solute particles
Na+ extracellular
K+ intracellular
Water will move towards areas of high solute conc
What are the components of extracellular fluid?
Extravascular/interstitial fluid - fluid between cells
Intravascular
fluid
Describe the components of extracellular fluid
Proteis
Na+
Cl-
HCO3-
Capillary membrane freely permeable to water and electrolytes
Describe the components of intracellular fluid
K+
Cell membrane freely permeable to water only
What are starling’s forces?
Hydrostatic pressure
Oncotic pressure
Osmotic pull
Permeability
What is osmotic pull/force
Water diffused from area of highest conc of water to area of lowest conc of water
What is hydrostatic pressure
Force that results from the pressure of a liquid (water) within a compartment
What is oncotic/colloid pressure?
induced by proteins which look to pull water back into plasma - opposite to hydrostatic pressure
Describe the balance of forces that balances water movement in and out of capillaries
Define tonicity
osmotic pressure of solution relative to the plasma
isotonic = same osmotic pressure as plasma
Define osmolarity
conc of particles dissolved in a fluid per L
Define osmolality
Conc of particles dissolved in a fluid per kg
If osmotic pressure/osmolarity is too high in the plasma where will fluid flow?
into plasma
If a solution is hypertonic what is its concentration compared to plasma?
more concentrated
What is an effective osmole?
a solute that does not freely cross the membrane, e.g., Na+, K+
