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Sympathetic Nervous System
Part of the autonomic nervous system and responsible for directing the involuntary, visceral actions of muscles, blood vessels, and glands. Generally, the autonomic nervous system regulates the physiological arousal that accompanies experienced emotions. For example, the sympathetic nervous system mobilizes bodily resources to take action. If a person feels threatened, consequently, heart rate, blood pressure, breathing, and perspiration may increase. This is referred to as the fight-or-flight response, as the body can respond to the threat by either “fighting” or “fleeing” the perceived threat. As the body cannot remain in this mobilized and alert state, the parasympathetic nervous system is responsible for counteracting and normalizing the physiological arousal state. The sympathetic nervous system also lessens blood flow if there is an injury to the body.