Resting Membrane Potential

1
Resting Membrane Potential

• Whitney Theis
• March 31, 2006

2
Charge of a Cell

• Normally a cell is more negative on the inside
• On average -70mV
• The negative charge forms a thin layer along the
  inside of the membrane

3
Major Players in Resting Potential

• Na, K, and Cl-
• The resting potential due to the efflux of K out
  of the cell
• Leaky channels
• Relative concentrations

4
Development of Resting Potential

• Cell thrown out of resting potential when impulse
  occurs across membrane
• When this happens the ATPase pump offsets the
  action
• There are K and Na channels that are always open
• K flows out faster than Na

5
ATPase Pump

• Allows two potassium ions in and three sodium
  ions out
• This pump offsets the slow leak of Na into the
  cell
• The leaky potassium channels are not offset by
  the pump
• Thus membrane potential due to eflux of potassium