Final answer:
The osmolality of plasma is approximately 285 mOsm/kg, which is indicative of a healthy balance of water and solutes in the body's fluids.
Step-by-step explanation:
The osmolality of plasma, which reflects the state of hydration in the body, is typically maintained within a narrow range. A normal plasma osmolality value is approximately 285 mOsm/kg. This value indicates a balance between the amount of water and solutes present in the blood plasma.
Osmolality measures moles of solute per kilogram of solvent, and it is an important factor when considering solutions like saline that are isotonic with body fluids. Plasma osmolality is carefully regulated by mechanisms that manage both water intake and output to prevent imbalances that could lead to hypotonicity or hypertonicity.