pet*pet said:
having a little confusion with depolaristion and polarisation cos i've being my teacher said that when cell membranes are depolarised that is the resting potential and when its polarised thats when theres and impulse action potential while i saw some other info saying the resting potential is when cell is polarised..like completely opposite ...so which one is correct or do they mean the same thing ?? =\ much appreciated if anyone can help >.<
basically, your nerve which consists of neuronal fibres are at resting potential which is like -70mV yea, basically an action potential is a change in potential, a positive change that is taht enables an impulse to be sent from one part of the body to another. IN this impulse are the involvement of sodium and potassium ions... ions are molecules with charge... in this case they are BOTH positively charged.
an action potential/ impulse is first initiated by depolarisation, which is when the ...wait first of all.. the
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internal is -ve..initially with potassium ions inside
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external is +ve initially with sodium ions outside
basically depolarisation is when the sodium ions from the outside move in to the internal of the membrane through sodium channels/gates and this makes the inside more POSITIVE because there are sodium AND potassium inside which are both positives...this increases the positivity and passes the threshold to ignite an impulse. From there the positivity, at which it reaches its peak...must go down back to its -ve state
this is through repolarisation, whereby potassium ions move out of the internal membrane to the outside through the potassium channels. This makes the inside more -vely charged, but then this is when hyperpolarisation i think happens, where the charge goes too -ve and goe sbelow its resting potential of -70...so like -80mV...from here the sodium/potassium pump kicks in, it basically moves all the potassium from the outside inside and the sodium inside back out as its suppose to be...this is done through active transport
if anythigns wrong here, notify me of it... ij ust learnt it
