cn any 1 post me hw is action potential transmitted??? pls??? its urgent!!!!
Resting neurones have a potential difference across their cell membranes. The outer surface of the membrane is positively charged and the inner surface is negatively charged. This is the resting potential.
The resting potential is generated by the N+/K+ Pump and a potassium channel in the membrane. The pump moves 3 sodium ions out of the cell by active transport and pumps 2 potassium ions in to the cell. The potassium channel allows facilitated diffusion of potassium ions back out of the cell. Thus creating a more positive extracellular fluid than that of the inner membrane. This is because more positive ions leave the cell than enter in to it.
The pumps work continuously, but the channel proteins (potassium channels) can be opened or closed.
Depolarisation of neurone cell membranes involves another channel protein, sodium channels. If a neurone is stimulated, sodium channels open and sodium ions diffuse into the membrane - increasing the positive charge inside the cell due to their positive charge (Na+), so the charge across the membrane is reversed. This is action potential and the membrane depolarises.
When sodium ions diffuse into the cell, this stimulates nearby sections of membrane and more sodium channels open. Once they've opened, the channels recover and close again.
Hope this helps!
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