The resting membrane potential of a neuron is determined by concentration gradients of ions like potassium, sodium, and chloride across the neuronal membrane. At rest, the intracellular concentration of potassium is higher than extracellular, while sodium is higher extracellular than intracellular. This creates an electrochemical gradient that drives the passive diffusion of potassium out of and sodium into the cell. However, the membrane is more permeable to potassium than sodium, resulting in a steady resting potential of around -70 mV, with the inside of the cell being negatively charged relative to the outside. Ion channels including passive leak channels and voltage-gated channels regulate ion flow and influence changes in membrane potential during neuronal signaling.

1. RESTING MEMBRANE
POTENTIAL
Presented by:
Artist Rimsha
Zoologist

2. introduction
 A resting (non-signaling) neuron has a voltage
across its membrane called the resting membrane
potential, or simply the resting potential.
 The resting potential is determined by concentration
gradients of ions across the membrane and by
membrane permeability to each type of ion.

3. Types of ions which are involve
 Potassium ions
 Sodium ions
 Chloride ions
 In a resting neuron, there are concentration gradients
across the membrane for Na+ and K+. ions move down
their gradient via channels, leading to separation of a
charge by create the resting potential.
 The membrane is much more permeable to k+ then to
Na+. So the resting potential is close to the equilibrium
potential of K+.

4. Role of ion channels
Types of plasma membrane ion channels:
 Passive, or leakage, channels – always open
 Chemically gated channels – open with binding of a
specific neurotransmitter
 Voltage-gated channels – open and close in response to
membrane potential (change in charge)
 Mechanically gated channels – open and close in
response to physical deformation of receptors

5. Operation of chemical Gated Channel

6. Operation of a Voltage-Gated Channel

7. Gated Channels
When gated channels are open:
 Ions move along chemical gradients, diffusion from high
concentration to low concentration.
 Ions move along electrical gradients, towards the
opposite charge.
Together they are called the Electrochemical Gradient
 An electrical current and Voltage changes are created
across the membrane

8. Resting Membrane Potential
• The potential difference (–70 mV) across the
membrane of a resting neuron.
• It is generated by different concentrations of
Na+, K+, Cl, and protein anions (A)
• The cytoplasm inside a cell is negative and the
outside of the cell is positive. (Polarized)

9. diagram

10. Changes in Membrane Potential
Changes are caused by three events
Depolarization ;
The inside of the membrane becomes less negative.
Repolarization:
The membrane returns to its resting membrane
potential.
Hyperpolarization :
The inside of the membrane becomes more negative
than the resting potential

11. Changes in Membrane Potential

12. Reference
1. Loew, L. M., & Lewis, A. (2015). Second Harmonic
Imaging of Membrane Potential. Advances in Experimental
Medicine and Biology, 473-492. doi:10.1007/978-3-319-17641-
3_19
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