Question

What is the advantage of a thicker axon over a thinner axon?
Apparently, the conduction velocity of the AP is faster for a thicker axon, but I do not understand why.

Answer 1

I think this is a physical property of the axon - the resistance is less for an axon of larger diameter. The squid giant axon is an evolutionary adaptation which uses this property. There's a bit about the squid giant axon here:

http://en.wikipedia.org/wiki/Squid_giant_axon

Hope this helps explain things.

Answer 2

actualy the term thicker means covering of mylien sheath and nerve conduction is v.fast in mylien sheath axon

Answer 3

Whilst I agree with Heena that a myelinated axon is much faster than one of the same size which has no myelination, the size of the axon is important as I said earlier. The axon is the bit of the nerve cell which extends and synapses with other cells whereas the myelination comes from another cell.