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.
In myelinated axons, there are unmyelinated gaps between the numerous myelin sheaths surrounding the same myelinated axon. These gaps are called nodes of Ranvier. A change in voltage across the plasma membrane of an unmyelinated portion of axon is called an action potential.ction Potentials. Not all of the axons in your body contain a myelin sheath; we call these axons unmyelinated axons. Whether an axon is myelinated or not, the axon will still transmit an electrical impulse from one cell to another.