Bodily fluids Flashcards
What percentage of our body weight is water?
50-70%
What is TBW and what is it composed of?
Total body water = ECF (extracellular fluid) + ICF (intracellular fluid)
What is are the amounts of ECF and ICF in the body?
1/3 of TBW = ECF 2/3 = ICF
What are the types of extracellular fluid?
Plasma volume (PV) and interstitial fluid
What percentage of our ECF is plasma volume? What percentage is interstitial fluid?
20% Plasma volume 80% interstitial fluid
What is our blood volume?
Plasma volume + volume of blood cells (hematocrit)
What is a normal hematocrit?
~45%
What is transcellular fluid?
A small part of ECF inside organs (e.g. cerebrospinal fluid) It is ignored in calculations
What is the standard osmolality of body fluids?
285 mOsm/kg
What types of fluid/body compartments are similar? Different?
Interstitial fluid and plasma are nearly identical (highly permeable endothelium) while intracellular fluid is markedly different (due to PM)
What are the primary (highest concentration) ions in the intracellular fluid?
K+ (highest), phosphates, and some Mg++ and proteins
What are the primary (highest concentration) ions in the extracellular fluid?
Na+ (highest), Cl- with some bicarb
Is the net charge neutral in the ICF? in the ECF?
Neutral in both
How is solute flux defined?
The number of molecules (or moles) crossing the unit area in the unit time
What is the equation for flux of a neutral solute at concentrations C1 and C2?
J = P(C1 - C2) = P x (delta)C P = permeability J = flux