Neurones... (1 Viewer)

[Jono10]

Im nearly finished my study notes for communication, and i have to say this is the first time that ive had trouble with somethin in bio.

My problem is with this dot point:

identify neurones as nerve cells that are the transmitters of signals by electro-chemical changes in their membranes

I dont get it at all, ive read through it heaps, looked it up in the dot point book, looked online, its sooo difficult. The main part im having problem with understanding is the ion parts, aswell as the potential differences, resting..... Its just so confusing

If anyone could try and explain it in as much detail but easy to understand, it would be a great help. Please dont link me to other sites, id prefer it if you explained it in your own words (unless its to a picture)

Also, if yyour going to include words like potencial difference, polarity, and all those, please tell me what they mean aswell.

If anyone could help me with this, id greatly appreciate it

 

[jest3r]

I'll try to break down the key concepts that you should become familiar with...

Resting membrane potential of neuron (neural cell) - this when the neuron is in its "steady" state, no stimulus has activated it therefore there's no net movement of Na+ or K+ ions into or out of the neuron. If we were to hook up a voltmeter to a single neuron (if it were possible), we would get a measurement of -70 mV.

Threshold membrane potential - this is the membrane potential required to set off an action potential in the neuron...which is -55 mV. So a stimulus must be strong enough to "push" the neuron membrane potential to -55 mV in order to set off an action potential. If it's not strong enough, there's no action potential, hence all its an "all or nothing" process.

Action Potential - this describes both the rush of Na+ ions into the cell (depolarisation) and K+ ions out of the cell (repolarisation). Na+ ion influx during depolarization abruptly stops when the membrane potential reaches a certain point (i.e. +30 mV). Once Na+ ions have ceased moving into the neuron, K+ ions rush out of the cell (repolarization) and the neuron is restored to its resting state.

Depolarization - rapid movement of Na+ into the neuron hence the inside of the neuron becomes more +ve.

Repolarization - rapid movement of K+ out of the cell hence the inside of the neuron becomes more -ve.

This diagram should be of some use:
http://content.answers.com/main/content/img/oxford/Oxford_Sports/0199210896.action-potential.1.jpg

Hope this helps. Good luck