Hypertonic Solution: Definition, Effect & Example

What is a Hypertonic Solution?

Though the cell is the basic unit of all life, there is nothing basic about it. Cells require very specific conditions to be able to function properly. Temperature and the amount of water and nutrients must all be just right in order for a cell to be healthy, and these optimal conditions vary depending on the organism.

The amount of fluid both inside and outside a cell is one condition that is very important, and this fluid amount is often determined by the amount of solutes outside of the cell. Solutes are the particles that are dissolved in a solvent, and together they form a solution. In your body, these solutes are ions like sodium and potassium.

There are three types of solutions that can occur in your body based on solute concentration: isotonic, hypotonic, and hypertonic. An isotonic solution is one in which the concentration of solutes is the same both inside and outside of the cell. A hypotonic solution is one in which the concentration of solutes is greater inside the cell than outside of it, and a hypertonic solution is one where the concentration of solutes is greater outside the cell than inside it.

How Different Solutions Affect Your Cells

For the cells in your body, the ideal solution is an isotonic solution. This is because water (which is the major solvent in your body) likes to diffuse from an area of low-solute concentration to an area of high-solute concentration. This process is called osmosis. Water does this because, by diffusing to where there are more solutes, it essentially evens out the ratio of solvent and solute.

When human cells are in a hypotonic solution, water will rush into the cell by osmosis, which is not good for the cell because it will fill with water and burst, or lyse. Plant cells actually prefer hypotonic solutions because they have a rigid cell wall that needs the pressure from extra water inside the cell to stay rigid and firm.

A hypertonic solution will do just the opposite to a cell since the concentration of solutes is greater outside of the cell than inside. For both human and plant cells, the water will rush out of the cell, and it will shrivel up. When this happens to a plant cell, it is called a plasmolyzed cell.