Donnan potential

Imagine you're playing with a toy box and you have a bunch of different toys. Some toys are heavy, and some are light. And when you put them in the toy box, they spread out and move around.

The same thing happens with chemicals in our body. We have different chemicals that are either positively charged (+) or negatively charged (-). And when we put them in a space, they spread out and move around too.

But sometimes we have a special space, like a cell membrane, that acts like a toy box with a divider in the middle. This divider only lets certain chemicals pass through. And when we put our positively charged and negatively charged chemicals on either side of the divider, something interesting happens.

The positively charged chemicals will start to push against the divider because they want to get through. And the negatively charged chemicals will push back against them because they don't want to mix with the positively charged ones.

This creates a special type of electric pressure that's called a Donnan potential. The Donnan potential is basically like a barrier that separates the positively charged and negatively charged chemicals. And it can influence how other chemicals move and interact with each other.

So just like how you can separate your toys in your toy box with dividers, our body has special cells that can use the Donnan potential to keep certain chemicals separated too.