What characterizes an isotonic solution?

An isotonic solution is characterized by having an equal concentration of solutes inside and outside the cell. This balance ensures that there is no net movement of water in or out of the cell, which helps to maintain cellular integrity and function. When a cell is placed in an isotonic environment, the osmotic pressure is equalized, and the cell neither swells nor shrinks, thus preserving its shape and physiological processes. In practical terms, this is crucial for cells to operate optimally without experiencing stress from osmotic imbalances. This principle is vital in medical settings, especially when administering IV fluids or caring for patients where fluid balance is essential.