Membrane potential refers to the separation of opposite charges across a cell membrane. This separation of charges creates a difference in the number of cations and anions and has the potential for work. There are two types of membrane potentials: graded potentials and action potentials. Graded potentials have a variable magnitude, occur over short distances, and depend on the strength of stimulation. Action potentials have a constant magnitude, occur over long distances, and result from stimulation reaching a threshold level.

2. Membrane potential refers to a separation of
opposite charges across the membrane or to a difference
in the relative number of cations and anions.
 A separation of charges across the membrane is
called a membrane potential because separated
charges have the potential to do work.
 Potential is measured in volts.
Types
 Graded Potential
 Action Potential

3. Graded Potential Action Potential
i. Variable Magnitude
ii. Decremental
iii. Spatial or Temporal
iv. No Refractory period
v. Trigger NTs, Hormones
vi. Occur at Cell body
vii. Variable direction
viii. Chemically gated ionic channels
ix. Short distance(1-2mm)
x. Reversible
xi. Passive spread
xii. Limited to local effects
xiii. Depends on stimulus
xiv. Occur in most plasma membrane
xv. Stimulus can’t reach threshold
xvi. Produced by net movement of ions
xvii.Hyperpolarization/depolarization
xviii.Slow
i. Constant
ii. Non-Decremental
iii. No summation
iv. Absolute+ Relative Period
v. Trigger Threshold
vi. Occur at Axon Hillock
vii. 1 way direction
viii. Voltage gated ions channel
ix. Long Distance
x. Non-Reversible
xi. Self-propagating
xii. Produce Distant effects
xiii. All or None Response
xiv. Only in excitable membranes
xv. Stimulus Reach Threshold
xvi. Produced by sequential Membranes
xvii.Always Depolarization
xviii.Rapid

4. Graded
Potential
Action Potential