Defining Hypertonic Solution
A hypertonic solution is a solution that has a higher concentration of solutes (dissolved particles) and, consequently, a lower concentration of water compared to another solution, typically the inside of a cell. When a cell is placed in a hypertonic solution, there is a net movement of water molecules out of the cell.
Effects on Cells
Due to osmosis, water moves from an area of higher water concentration (inside the cell) to an area of lower water concentration (the hypertonic solution) across the cell's semi-permeable membrane. This outflow of water causes animal cells to shrink or crenate, losing their normal shape. In plant cells, the cell membrane pulls away from the cell wall, a process called plasmolysis, though the rigid cell wall prevents the entire cell from shrinking dramatically.
A Practical Example
Imagine placing a fresh grape (which contains cells with a certain solute concentration) into a highly concentrated sugar syrup. The sugar syrup is a hypertonic solution relative to the grape's cells. Water will exit the grape cells and move into the syrup, causing the grape to shrivel and become a raisin. This demonstrates the osmotic effect of a hypertonic environment.
Importance in Biology and Medicine
Understanding hypertonic solutions is crucial in various biological and medical contexts. For instance, consuming extremely salty food can lead to body cells losing water. In medicine, hypertonic saline solutions might be used to reduce swelling in certain tissues by drawing water out of cells, while intravenous fluids must be carefully formulated to be isotonic to prevent damage to red blood cells.