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Hypertonic and hypotonic

I cannot remember which one is which and I keep getting them confused.

Hyper=more , hypo=less is how I remember it. Works with all the words that have these prefixes (e.g. hypertension/ hypotension) :biggrin:

Reply 2

Winter_Ivy

Hypertonic means that the extracellular concentration of ions is higher than the one in the cell, which will lead to increase in the osmotic pressure and according to the osmotic gradient the water will leave the cell to dissolve the extracellular environment (leading to plasmolysis). For hypotonic is the other way around,i.e the outside has less concentration of ions than intracellularly which will lead to the water entering the cell (hemolysis for red blood cells). The way my teacher explained it to me is that the water is always moving from low concentrations of ions to high concentration of ions (which is the osmotic gradient) and it's trying to equalize the two environments in a way by "dissolving" the more concentrated one :biggrin:

But obviously it's not great for a cell that needs an isotonic solution to survive (where the osmotic pressure is zero and there will be no drastic movement of water). Once you see the logic behind it it's so easy to understand :smile: