Neve signal amplication

[Abu Anzar]

I need a review on nerve signal amplification.
That how impulse travel from 1 end to another? and
do its strength remain same or not if same than how as traveling from 1 pt. to other must bear some lose?

[Darby]

An impulse is a wave of gates opening in the axon membrane, allowing ions that have been pumped into a very uneven outside/inside distribution to flow back VERY quickly (and opening the gates farther along). After the signal passes, the gates close and the pumps reset the membrane potential.

This produces a signal that is generated and regenerated as it travels, which is why it holds its strength. That is, as long as the potential can be set, and some diseases interfere with that.

Signal strength varies from nerve to nerve, but not ON the same nerve - stronger signals come from a bunch of signals sent one after the other.

What would you be amplifying the signal for?

[Dr.Stein]

I won't say anything, just enjoy this:

http://highered.mcgraw-hill.com/olcweb/ ... lification

[Abu Anzar]

I am not amplifying signal right now may be after 3 yrs and 10 months.. actually I asked this for raising a question which is based on impedance. I'll ask here very soon just by collecting some material on signal amplification.

Thanks for presentation Dr. Stein and Darby for replying

[Abu Anzar]

Dr. stein do such marvel presentations are available on other topics also if yes than kindly write there links here

Thanks in advance

[Abu Anzar]

If I sum up what u said is that:

signal traveling in nerve decreases its strength but at the same time due to channels it gain its strength back

i.e. let suppose two ends of nerve a and b
impulse be the strength of 2
and a1 be intermediate points

impulse start moving from a and move towards b..

the strength of impulse while traveling from a to a1 decreases some of its strength i.e. decreases from 2 to 1 but due to channels it re-gain its original strength 2 .. similarly while moving from a1 to b it loses its strength and re-gain its original strength and at the end, the strength of signal/impulse remains same as it was at point a

Am I right?

[Dr.Stein]

Dr. stein do such marvel presentations are available on other topics also if yes than kindly write there links here

Thanks in advance

Yes, they are under McGraw-Hill. Another animations I have are from Benjamin Cummings, Pearson, and Garland. Besides available in the net, they are also included in CD, which is attached the book if you purchase it They also provide materials for transparancy slides, exams, tasks, etc. nice things but you need a registration number/key/code or whaterver it is called. You can get it in your original book, however none works for me

[Darby]

Abu Anzar - the strength does sort of reset at the synapses, but it doesn't decrease along the way - think of the signal this way.

Along a wall is a series of light switches, all for the same strength bulbs. Standing at those switches is a person.

Each person's job is to -
- flip the switch when poked.
- after flipping the switch, poke the next person.
- after poking the next person, flipping the switch off again.

This signal of lights-in-series doesn't weaken with distance, since the strength is local, not propagated. It's always the same strength (unless some outside force affects it), and since the "people" are all identical, it's always moving at the same velocity. It can go faster in some systems, where the number of people and switches at each spot is higher (larger axons), or the people and switches are more efficient (myelinated axons).



On another note, I liked the animation link, but it's about a very different type of cell signalling.

[Abu Anzar]

Now its clear, to many extend
actually I am working on impedance that signals in nerve amplified but no impedance produced why.. ur answer has resolved this to many extend, I'll think on it further if any hurdle come across again than I'll be here again.

Thanks

[Darby]

You can't equate an axon with a wire - it's not the same kind of flow, so a property like impedance can't be applied the same way.

[Abu Anzar]

ok!
hmmmz
can u write the basic difference b//w them
except that in wire there is flow of charges and in nerve there is flow of ions, and resistance that is produced by wire and myelin sheath that increases the velocity of impulses

[canalon]

In axon there is no flow of ions per se. You should read a little on how the signal is going through This should be a good start:
http://en.wikipedia.org/wiki/Action_potential