Answer:
The two properties that determine the conduction velocity in a mammalian neuron are myelination and voltage-gated Na+ channel concentration.
Step-by-step explanation:
When the electrical stimulus is applied to the membrane of the axon it produces depolarization by activating the sodium voltage-dependent channels all along the axon. Besides, there is an increase in sodium permeability. Depolarization propagates to inactivated regions adjacent to the membrane opening more sodium channels.
There is a directly proportional relationship between the fiber diameter and the conduction velocity. Mielinized fibers are thick and their conduction velocities are very fast.
The conduction velocity increases substantially in myelinated fibers because of the high concentrations of sodium channels in the Ranvier nodes that are not myelinated areas and the diameter of the axon becomes thinner.