Describe the action potential in terms of the different functional states of the voltage- gated Na+ membrane channels (Note: there are three states)
Describe the action potential in terms of the different functional states of the voltage- gated Na+ membrane channels (Note: there are three states)
Introduction
Action potential is the short term change in the electric potential on the cell’s surface in response to stimulus which then results in the transmission of an electrical impulse which travel across the membrane. This will make the nerve cells to transmit a signal over a distance. This can happen in all types of cells.
A characteristic pattern of rapid rise and fall in the voltage or membrane potential across the cell membrane is action potential. These are generated as a result of various types of voltage gated ion channels which are present embedded in the plasma membrane of the cell. In neurons, the action potential play a vital role in cell to cell communication.
Generation of action potential:
- Stimulus from the sensory cell will cause the target cell to get depolarized toward the threshold potential.
- If the threshold is reached, it will result in the opening of all of the sodium ion channels and the depolarisation of the membrane.
- At the peak of action potential, potassium ion channels open and begin to leave the cell while the sodium ion channel closed simultaneously.
- As potassium ions are leaving the cell this result in the hyperpolarisation of the cell membrane.
- The sodium ion channel get closed and sodium or potassium ion transporter restores the resting potential.
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