Exam 1 Flashcards
(189 cards)
process when water is driven by osmotic gradients through a semipermeable membrane separating solutions with different solute concentration
osmosis
TBW in water:
Male % and Liters
Female % and Liters
Infant %
Male 60% and 42L
Female 50% and 39L
Infant 75%
% of total body weight of the following fluid compartments:
TBW
ECF
ICF
RBC in Liters of H2O?
% of ECF that is:
ISF
Plasma
TBW 60%
ECF 20%
ICF 40%
RBC= ~1.5L of H2O
ISF = 75% of ECF Plasma = 25% ECF
Approx total blood volume in an adult male in liters
~5L - Plasma (3.5L) + RBCs (1.5L)
2 fluid types in the ECF (related to movement)
functional and sequestered
osmosis is a passive process driven by differences in particle _______, not size.
numbers
pressure gradient created by solute molecules that displace water
osmotic pressure
molecules move through a semipermeable membrane from an area of higher concentration to an area of lower concentration
diffusion
movement of molecules against their electrochemical gradient in a process that requires energy. [e.g. Na+/K+ATPase]
Active Transport
the force (mmHg) generated by the pressure of fluid within or outside of a capillary on the capillary wall
Hydrostatic Pressure
osmotic pressure (mmHg) exerted by proteins in the blood plasma or interstitial fluid
Colloid Osmotic Pressure (Oncotic Pressure)
number of osmotically active particles per liter of solvent; mOsm/L
Osmolarity
number of osmotically active particles per kilogram of solvent (water); mOsm/kg
Osmolality
Plasma Osmolality formula
2[serum Na+] + [Glucose]/18 + [BUN]/2.8
Normal = 280-290 mOsm/kg
Osmolal Gap: measured osmolality >10 mOsm/kg H2O than calculated
in a fluid compartment, the sum of all positive ions (cations) exactly equals the sum of all negative ions (anions)
Law of Electrical Neutrality
intracellular and intravascular concentration of electrolyte in mEq/L Na+ K+ Ca++ Ma+ Cl-
ion - ICC, IVC Na+ = 10, 134-145 K+ = 156, 3.5-5 Ca++ = 3, 5 Ma++ = 26, 3 Cl- = 2, 103
what ion contributes the greatest to determining osmolality?
Na+
Physiologically, ______ and _____ are the primary determinants of tonicity
sodium, potassium
Isotonic solutions
BSS; Normosol™-R or Plasma-Lyte
Hypertonic solutions
0.9% NaCl is slightly hypertonic; 3% NaCl or 20% mannitol is very hypertonic
Hypotonic solutions
Lactated Ringer’s (LR) slightly hypotonic; 0.45% NaCl and D5W are hypotonic
ICF has high concentrations of which ions?
Potassium (K+): 156 mEq/kg H2O
Magnesium (Mg2+): 26 mEq/kg H2O
Phosphate (P04-): 108 mEq/kg H2O
Proteins 55 mEq/kg H2O
*notice this mEq/kg and relates to osmolality
ICF has low concentrations of which ions?
Sodium (Na+): 10 mEq/kg H2O
Chloride (Cl-): 2 mEq/kg H2O
Calcium (Ca2+): 3 mEq/kg H2O
*notice this mEq/kg and relates to osmolality
ECF has high concentrations of which ions?
Sodium (Na+): 136 - 145 mEq/L
Chloride (Cl-): ~110 mEq/L
Calcium (Ca2+): ~4 mEq/L
*notice this mEq/L and relates to osmolarity