Knowledge center. Amphetamines are drugs which stimulate the CNS (central nervous system) - they are psychostimulant drugs-when overused they can be psychologically and physically addictive. As well as giving the user an enhanced feeling of wakefulness and focus, they also reduce appetite.mphetamines stimulate the central nervous system and the sympathetic part of the peripheral nervous system. Experts say that amphetamines enhance the synaptic activity of three neurotransmitters-dopamine, serotonin and norepinephrine.
Propagation of action potential along myelinated nerve fiber. Saltatory conduction (from the Latin saltare, to hop or leap) is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials.n addition to increasing the speed of the nerve impulse, the myelin sheath helps in reducing energy expenditure over the axon membrane as a whole, because the amount of sodium and potassium ions that need to be pumped to bring the concentrations back to the resting state following each action potential is decreased.
As a nerve carries electrical impulses from one end to the other, myelin helps to stop the impulse from leaving the axon and increases electrical resistance, therefore enhancing signal conduction. Myelin insulates the axon by assembling specialized structures at the nodes of Ranvier.