Nerve impulse = the transmission of action potential along the axon of a neurone.
Factors affecting the speed of the nerve impulse:
MYELIN SHEATH - This acts as an electrical insulator which prevents action potential forming in the part of the axon covered by the myelin sheath. Action potential can, however jump from node to node in the nodes of Ranvier - this is saltatory conduction. This can increase the speed of conductance.
DIAMETER OF THE AXON - Greater the diameter, the faster the speed due to less leakage of ions making it easier to maintrain membrane potentials.
TEMPERATURE - Higher the temperature, the faster the speed due to active transport energy coming from respiration which is controlled by enzymes.
THE REFRACTORY PERIOD.
In this period, after the action potential has…