Ion channels

 

How cells exchange information with surrounding cells and pass on substances was unclear for a long time because the cell membrane is not permeable even for the most miniscule particles.

Today we know that there are pores in the cell membrane which function like tiny channels. The pores are made of proteins. Each channel only allows certain substances to pass through them. The task of one kind of the pores is to allow so-called ions, electrically charged salt particles to pass in and out of the cells. That is why these pores are called ion channels. Different channels only let specific salt particles through, i.e. there are channels that only let calcium ions pass through.
The channels receive the impulse for opening and closing the gates through electrical signals in the cell membrane or through messenger substances which can dock onto certain sites on the surface of the cell membrane.

Many diseases of the nervous system– for instance different kinds of epilepsy – are due to defective ion channels.