Conduction of the Signal

Unmyelinated Fibers
have voltage-reg. gates along the entire axolemma
when APs occur at the trigger zone:
Na+ enters and diffuses to adjacent areas
opening voltage gates just distal to the AP
Na+ and K+ gates open and close as at the trigger zone
this excites the membrane just distally
chain reaction travels to the end of the axon
relatively slow in unmyelinated axons
Myelinated Fibers
voltage-reg. gates are scarce in the internodes
400 times more at the nodes
Na+ cant diffuse anyway due to myelin sheath
so the APs jump from node to node:
Saltatory conduction
transmit the signal much faster