Tonicity

Definition

Tonicity is the ability of a solution to affect the volume and pressure of a cell by osmosis. It is primarily determined by the concentration of non-penetrating solutes.

5 Must Know Facts For Your Next Test

1. Tonicity is categorized into three types: isotonic, hypertonic, and hypotonic.
2. An isotonic solution has the same solute concentration as inside the cell, causing no net water movement.
3. A hypertonic solution has a higher solute concentration than inside the cell, causing water to move out of the cell, leading to cell shrinkage.
4. A hypotonic solution has a lower solute concentration than inside the cell, causing water to move into the cell, leading to swelling or bursting.
5. Understanding tonicity is crucial for administering IV fluids correctly in clinical settings.

Review Questions

• What happens to a cell placed in a hypertonic solution?
• How does an isotonic solution affect cell volume?
• Why is tonicity important in medical treatments?

Related terms

Osmosis:

The movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration.

Osmolality:

The concentration of solutes per kilogram of solvent, often used interchangeably with osmolarity.

Homeostasis:

The maintenance of stable internal conditions in an organism despite changes in external environments.