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The transmission of a nerve impulse along a neuron from one end to the other occurs as a result of electrical changes across the membrane of the neuron. The membrane of an unstimulated neuron is polarized—that is, there is a difference in electrical charge between the outside and inside of the membrane.
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The nervous system can respond quickly to stimuli, through the use of action potentials and neurotransmitters. Responses to nervous system stimulation are typically quick but short lived. The endocrine system responds to stimulation by secreting hormones into the circulatory system that travel to the target tissue.