Osmometry Flashcards
• measurement of the osmolality of an aqueous solution such as (3)
Osmometry
serum, plasma and urine;
measurement of the concentration of dissolve solute particles in a solution
Osmometry
of a solution is related to its colligative properties such as osmotic pressure, boiling point, freezing point, and vapor pressure.
Osmolality
are those properties of a solution that are only a function of the concentration (molality) of the particles in solution.
Colligative properties
TRUE OR FALSE
Ideally, the size of the particles, the mass of the particles, and the type of particles do not affect the colligative properties.
True
Only the____ of the particles(moles of particles per kg of solvent) matters in osmometry (colligative properties)
molality
The colligative properties are expressed as the affect that the particles in solution have on the solvent.
As the molality of the particles increases, it has the following effects on the solvent:
- The vapor pressure decreases
- The boiling point increases
- The freezing point decreases
• measurement is based on the change in electrical resistance across an aperture when a particle in conductive liquid passes through this aperture
ELECTRICAL IMPEDANCE
used primarily in the hematology laboratory to count leukocytes, erythrocytes, and platelets
ELECTRICAL IMPEDANCE
ASPIRATED BLOOD SAMPLE
Rbc platelet
Mixed with diluent
Cell Bath
Erythrocyte Count
Platelet Count
ASPIRATED BLOOD SAMPLE
Leukocyte count
Mixed with diluent and Cytochemical Stains
Lyses the RBCs only
Leukocyte Count
CELL BATH
Blood passes thru the____
Electrical current between____ changes each time a cell passes through
VOLTAGE PULSE
NUMBER OF PULSES =_____
aperture
electrode
CELL SIZE
platelets
2-20 fl (femtoliters)
erythrocytes
> 36 fl
LYSES OF RED BLOOD CELLS
Remaining Cells
LEUKOCYTE COUNT
= leukocytes
> 35 fL
