A student asks why osmolality is preferred over osmolarity as the measurement of osmotic activity in the clinical assessment of individuals. What response by the professor is most accurate?
A)Plasma contains sodium and chloride, which influence the volume of solution.
B)Volume affects perfusion more than the weight of solutes.
C)More of the weight of plasma is influenced by solutes rather than by water.
D)Osmotic activity depends on the concentration of solutes present in plasma.

Question

Quizplus · Accepted Answer

Osmolality is a measure of the number of milliosmoles per kilogram (mOsm/kg) of water, or the concentration of molecules per weight of water. Osmolarity is a measure of the number of milliosmoles per liter (mOsm/L) of solution, or the concentration of molecules per volume of solution. Osmolality is a measure of the number of milliosmoles per kilogram (mOsm/kg) of water, or the concentration of molecules per weight of water. Osmolarity is a measure of the number of milliosmoles per liter (mOsm/L) of solution, or the concentration of molecules per volume of solution. In plasma, less of the plasma weight is water; therefore the overall concentration of particles is greater. The osmolality will be greater than the osmolarity because of the smaller proportion of water. Osmolality is thus the preferred measure of osmotic activity in clinical assessment of individuals.

A Student Asks Why Osmolality Is Preferred Over Osmolarity as the Measurement