2013 Ion Channel Physiology

Biological circuits

Critical Fact icon All cells have a specific complement of channels, transporters and receptors that, in part, defines their unique physiology. By definition, all cells have a membrane potential. Ohm's Law defines the relationship among membrane potential (voltage), current and conductance (the inverse of resistance): I=CV. Most cells have a resting membrane potential (Vm or RMP) that is negative with respect to the extracellular fluid. Electrically excitable cells (neurons and myocytes) have a much larger RMP (-30 to -70 mV) because they have a larger number of K+ channels open at rest.
Flashlight Component

Parameter

Cell Component

Battery

Batteries

Force = Voltage
(also called the
electrical potential difference)

  • measured in Volts (V)

Cell membrane
Wires

Wires

Flow (current)

  • measured in Amperes (A)
Ion channels

Light

Flashlight

Resistance

  • measured in Ohms

Conductance (=1/R)

Switch

Switch

On/off

 

Email: Dr. Janet Fitzakerley | ©2013 University of Minnesota Medical School Duluth | Last modified: 21-sep-13 9:37 AM