What is an isotonic solution?

An isotonic solution is defined as a solution that has the same solute concentration as the inside of a cell. When a cell is placed in an isotonic solution, there is no net movement of water into or out of the cell because the concentration of solute particles is balanced on both sides of the cell membrane. This balance is crucial for maintaining cell shape and function, as it prevents the cell from swelling (which can occur in a hypotonic solution) or shrinking (which can occur in a hypertonic solution).

In biological systems, maintaining an isotonic environment is essential for the proper functioning of cells, allowing them to carry out necessary processes without disruptions caused by osmotic pressure changes. This concept is particularly relevant in medical settings, where isotonic saline solutions are often used for intravenous hydration to ensure that patient cells do not experience significant osmotic stress.