How much of us is fluid?
at least 50% at any point in our life newborn 80 childhood 65 adults 55 older adult 50
What is osmolality?
particles in a given WEIGHT of fluid
what is osmolarity?
particles in a given VOLUME of fluid
a serum ______ is a method of determining if someone is over/de hydrated
a serum osmolarity is a method of determining if someone is over/de hydrated
normal serum osmolarity range
280-300 mOsm/L
too high a serum osmolarity indicates
dehydration (too many solutes)
too low a serum osmolarity indicates
fluid overload (less solutes)
where is majority of fluid?
intracellular
-2/3
Intracellular fluid contains
potassium, phosphate, sulfate
fluid volume outside of the cell
1/3 extracellular
extracellular fluid contains
sodium, chloride, bicarbonate
what is the fluid called that is inside the blood vessels?
intravascular
what is the fluid called in between the cells?
interstitial
what 3 components determine the fluid balance in extracellular compartments?
what is osmotic pressure?
pressure exerted to prevent movement of water out of the intravascular space
pressure exerted to keep h20 in blood vessels
what is colloid oncotic pressure?
proteins attract water and hold onto water
what is hydrostatic pressure?
pressure of blood against the vessel wall
-causes filtration of a fluid from an area of high pressure to low pressure
what effects hydrostatic blood pressure?
arterial BP, Venous pressure, rate of blood flow
What is filtration pressure?
How does tonicity effect movement of fluid?
disrupts filtration pressure
3 kinds of tonicity
isotonic, hypotonic, hypertonic
What is an isotonic solution?
- equal concentration of water and electrolytes
what is a hypotonic solution in relation to cells?
-concentration of electrolytes outside cell is lower
-concentration of water outside cell is higher
(more water with less stuff outside the cell)
what is hypertonic solution in relation to cells?
-concentration of electrolytes outside cell is higher
-concentration of water outside cell is lower
(less water with more stuff outside the cell)