What occurs to a red blood cell when placed in a hypotonic solution?

When a red blood cell is placed in a hypotonic solution, the concentration of solutes outside the cell is lower than the concentration of solutes inside the cell. This difference in solute concentration creates a situation where water moves into the cell through osmosis in an attempt to equalize the solute concentrations on both sides of the cell membrane.

As water flows into the red blood cell, it causes the cell to swell. If the influx of water continues unchecked, the cell can take in so much water that it exceeds its capacity, leading to membrane rupture. This process is known as lysis, resulting in the red blood cell bursting. Therefore, in a hypotonic solution, the primary and expected effect is that the red blood cell will burst due to the osmotic imbalance.

This understanding of osmotic pressure and the behavior of cells in different tonicities is vital in critical care, particularly when dealing with fluid therapy and electrolyte imbalances.