Osmotic Balance
Biology: Cambridge International GCSE Supplement, topic 3.2.5
Osmotic Balance
Blood must be kept at the same water potential as blood cells (and other body cells) so that cells do not burst or shrink.
Low water potential
- A low water potential solution (hypertonic) has a lower water concentration and a higher ion concentration than cells.
- If the blood becomes too concentrated, cells lose water by osmosis and shrink.
High water potential
- A high water potential solution (hypotonic) has a higher water concentration and a lower ion concentration than cells.
- If the blood becomes too dilute, cells gain water by osmosis and burst.
Equal water potential
- Blood normally has the same water and ion concentration as cells (isotonic).
- Homeostasis works to regulate the blood's water and ion concentrations so that water does not move into or out of cells.
Test yourself on Osmotic Balance
Which of these is not true of a solution with a high water potential?