DIFFUSION POTENTIAL, RESTIN
MEMBRANE POTENTIAL AND ACT
POTENTIAL
A.N Malik
, Ion channels
• They are integral proteins that permit passage of specific ions
• Properties of ion channels
• Selective: allow passage of ions of specific sizes or charge e.g. a sodium
channel for only sodium ions…chloride ions wont pass
• Exist in open or closed state: Open state when ions are passing through
while closed state when no ions are passion thro
• Conductance/permeability: probability that a channel is open.
Opening and closing (gating) of a channel can be achieved thro:
• Voltage gating/based on membrane potential e.g. activation and
inactivation gates for sodium
• Ligand gated: opened or closed by hormones, neurotransmitters or secon
messengers e.g. nicotinic receptor for acetylcholine at the motor end
plate. When open it allows passage of both sodium and potassium
MEMBRANE POTENTIAL AND ACT
POTENTIAL
A.N Malik
, Ion channels
• They are integral proteins that permit passage of specific ions
• Properties of ion channels
• Selective: allow passage of ions of specific sizes or charge e.g. a sodium
channel for only sodium ions…chloride ions wont pass
• Exist in open or closed state: Open state when ions are passing through
while closed state when no ions are passion thro
• Conductance/permeability: probability that a channel is open.
Opening and closing (gating) of a channel can be achieved thro:
• Voltage gating/based on membrane potential e.g. activation and
inactivation gates for sodium
• Ligand gated: opened or closed by hormones, neurotransmitters or secon
messengers e.g. nicotinic receptor for acetylcholine at the motor end
plate. When open it allows passage of both sodium and potassium
