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.
Others are 3 feet long. Some axons are covered in myelin. Myelin protects the axons and helps carry axon messages as quickly as possible. Myelin. Myelin is made of membrane layers that cover an axon. This is similar to the idea of an electrical wire with coating to protect the metal underneath. Myelin allows a nerve signal to travel faster. In unmyelinated neurons, a signal can travel along the nerves at about 1 meter per second. In a myelinated neuron, the signal can travel 100 meters per second. Certain diseases can damage myelin. Demyelination slows down messages sent along axons and causes the axon to deteriorate.