Ions channels definition of ion channels: A protein that acts as a pore in a cell membrane and permits the selective passage of ions (such as potassium ions, sodium ions, and calcium ions),

Basic types of ions channels:  Leakage Ion channels: which are always open responsible for the resting membrane potential.  Gated channels: which open/close in response to a stimulus.

Classification of gated channels:  ligand-gated channels: Ion channels that open/close in response to a chemical messenger binding to the channel.  voltage-gated channel: Channels that open/close in response to a change in membrane potential.  mechanically gated channels: Open/close in response to a mechanical force on the membrane.

Models of gating  Discrete models : change in one region.  Generalized change: general structure change.  blocking particle: particle block the channel.

 ligand-gated channels:

 Mechanically gated channel:

 Ions channel diseases: