Membrane potentials

totodowo's version from 2015-09-13 20:51


Question Answer
Because they have no gates are always open for a specific ion.Ungated channels
Are channels sensitive to membrane voltage. The gates open and /or close in response to a membrane voltage changeVoltage-gated channels
Channels includes a receptor to a specific substrate or Ligand (Hormones, Neurotranmitters) Channels open and close when a ligand binds to themLigand-gated channels
Refers to the number channels that are open in a membraneMembrane conductance
If conductance is increasing, channels are opening If conductance is decreasing, channels are closingMembrane conductance
Is the Potential generated when a charged ions diffuse along the concentration gradient.Diffusion potential
The net force on an ion across a membrane is the sum of two independent forces: Concentration force & Electrical forceNet Force
Determined by the concentration difference across the membraneConcentration force
The size of the force is determined by the electrical difference across the membrane (usually measured in mV)Electrical force
Is defined as the diffusion potential of an ion across the membrane at equilibrium (at steady state)Equilibrium Potential
is used to calculate the equilibrium potential for an ion at a given concentration difference across the membrane.Nernst equation
the potential difference that exists across the cell membrane at rest Exists in all cells; but important for excitable cells such as nerve and musclesResting Membrane Potential (RMP)
It is the phenomenon of rapid depolarization followed by repolarization of membrane potential Action Potential or Impulse
It is the unique feature of excitable cellsAction Potential or Impulse
A period during which a second AP cannot be elicited with a threshold stimulusRefractory Period
the period during which another Action potential cannot be elicited, no matter how strong the stimulus is.Absolute Refractory Period
Begins at the end of Absolute Refractory period and continues until membrane potential returns to resting levels Relative Refractory Period
the period during which a second AP can be elicited by a stimulus stronger than the threshold.Relative Refractory Period
The speed of propagation of an action potential. Depends on two factors: a) Diameter of nerve fiber b) Myelination of nerve fiberConduction velocity (CV)