Chap 6 Resting Membrane Potential RMP
Chapter 6 Resting Membrane Potential (RMP)
What is the Resting Membrane Potential (RMP)?
ELECTRIC POTENTIAL – separation of opposite charges between 2 points. (“Has the potential to do electrical work if allowed to come together!”)
vs.
large potential difference small potential difference
Magnitude of charge separation = potential difference
** measured in volts (1 Volt = 1000 mV)
MEMBRANE POTENTIAL = charge separation across cell membrane (separation of overall net charge on either side of a membrane)
** The greater the difference in charge separation across the membrane the greater the membrane potential (greater voltage).
Potential difference (voltage across membrane)
Membrane potential (Sherwood, 1995)
Actual Cell Unequal distribution of ions across membrane (particularly Na+, K+ and A- (Anions).
[A-] trapped anions (neg. charged) inside cell ** Neg. charged proteins, DNA, RNA and ATP
ICF = intracellular fluid ECF = extracellular fluid ICF ECF
RESTING MEMBRANE POTENTIAL (RMP) Fig. 6.27 (Fox)
** voltmeter (needle electrodes)
RMP = - 70 mV
All cells in a “resting state” (no stimulation) have a separation of charges across the cell membrane (or RMP). The ICF (inside) is slightly more negative than the ECF.
Cell is like a small battery ready to discharge!
** By convention, the sign of the voltage designates the overall net charges inside the membrane as compared to the outside!
Ex.
An electric impulse is just a series of changes in membrane potential!
Change in MEMBRANE POTENTIAL (2 TYPES)
1. Graded Potentials
2. ** Action Potentials (AP)
A
What is the Resting Membrane Potential (RMP)?
ELECTRIC POTENTIAL – separation of opposite charges between 2 points. (“Has the potential to do electrical work if allowed to come together!”)
vs.
large potential difference small potential difference
Magnitude of charge separation = potential difference
** measured in volts (1 Volt = 1000 mV)
MEMBRANE POTENTIAL = charge separation across cell membrane (separation of overall net charge on either side of a membrane)
** The greater the difference in charge separation across the membrane the greater the membrane potential (greater voltage).
Potential difference (voltage across membrane)
Membrane potential (Sherwood, 1995)
Actual Cell Unequal distribution of ions across membrane (particularly Na+, K+ and A- (Anions).
[A-] trapped anions (neg. charged) inside cell ** Neg. charged proteins, DNA, RNA and ATP
ICF = intracellular fluid ECF = extracellular fluid ICF ECF
RESTING MEMBRANE POTENTIAL (RMP) Fig. 6.27 (Fox)
** voltmeter (needle electrodes)
RMP = - 70 mV
All cells in a “resting state” (no stimulation) have a separation of charges across the cell membrane (or RMP). The ICF (inside) is slightly more negative than the ECF.
Cell is like a small battery ready to discharge!
** By convention, the sign of the voltage designates the overall net charges inside the membrane as compared to the outside!
Ex.
An electric impulse is just a series of changes in membrane potential!
Change in MEMBRANE POTENTIAL (2 TYPES)
1. Graded Potentials
2. ** Action Potentials (AP)
A