DSA: Osmosis Flashcards
What is a SOLVENT?
Fluid that serves as the “base” for the solution
*In human body, the solvent is water
What is a SOLUTE?
Substance that is dissolved to make the solution
*In human body, solutes include the ions, proteins, steroids, etc…
Osmosis produces a significant change in the __________ of the two solutions; the more concentrated solution will _______ in volume as the solvent moves from the less concentrated solution to balance the two solutions
VOLUME, INCREASE
Describe DIFFUSION
- Movement of the solute across a membrane when there is a concentration gradient
- Moves from high concentration to low concentration
Describe OSMOSIS
- Movement of the SOLVENT
- Result in pressure gradient
In the body: the solvent is:
Water
In the body: solutes are:
ions, proteins
*Despite the different ion concentrations in the intra- versus extracellular fluid, the osmolarity of the two is _________
the same
*Osmosis ___________ the concentration of solutes
doesn’t depend on
*Osmosis only occurs if
There is a gradient for the water
Which ion(s) are in higher concentration in the ECF?
- Sodium
- Chloride
- Calcium
- Bicarbonate
Which ion(s) are in higher concentration in the ICF?
Potassium
The osmolarity of the ICF and ECF are:
THE SAME, no gradient for osmosis to occur
What does OSMOLARITY measure?
Number of osmotically active particles (solute) in the solution
Osmolarity is measured in units of ________
osmoles
In the body, osmolarity is measured in ________
milliosmoles (mOsm)
1/1000 of an Osmole
How to calculate osmolarity?
Osmolarity= g x [C]
Osmolarity calculation:
g=1 if:
the solute doesn’t dissociate
Osmolarity calculation:
examples of g=1?
Glucose, urea, proteins
Osmolarity calculation:
g>1 if:
the solute dissociates when placed in solution
Osmolarity calculation:
examples of g>1?
NaCl
g=2 if the NaCl were to completely dissociate into Na and Cl
The measured g=1.8 because not all the NaCl dissociates
CaCl2
g=3 at a max
What is the reflection coefficient?
Measure of the solute’s permeability across the membrane
Ranges b/w 0-1
0=solute is fully permeable across the membrane
1= solute is completely impermeable across the membrane
***Important b/c tells if OSMOSIS WILL OCCUR
If the reflection coefficient is 0, osmosis ______ occur
WILL NOT
If the reflection coefficient is 1, osmosis ______ occur
WILL