Osmotic pressure

Definition

Ability of a solution to change the volume of cells by attracting or repelling water, depending on impermeable solutes to the cell membrane.

How it works

Tonicty differs from osmolarity as it only considers impermeable solutes.

Role

Regulates cell volume and integrity via water movement.

Examples

• Isotonic solution 0.9% NaCl • Hypotonic solution: distilled water • Hypertonic solution: 10% glucose solution • Isotonic blood plasma

Recommendations

Intravenously administered solutions must be isotonic to prevent cellular damage.

Key takeaway

Tonicty is the direct determinant of cellular water movement and volume.

Related terms