GENERAL HISTOLOGY

Detailed explanation-1: -An isotonic solution is one that has the same concentration of solutes both inside and outside the cell.

Detailed explanation-2: -If the solution surrounding a cell is isotonic, water molecules diffuse in and out of the cell at the same rate by the process of osmosis. In this case there is no concentration gradient because the concentration of solute molecules is the same between the cell and the solution.

Detailed explanation-3: -If a cell is in a hypertonic solution, the solution has a lower water concentration than the cell cytosol, and water moves out of the cell until both solutions are isotonic. Cells placed in a hypotonic solution will take in water across their membranes until both the external solution and the cytosol are isotonic.