Sympathetic nervous system: Encyclopedia II - Sympathetic nervous system - Function

Sympathetic nervous system - Function

The sympathetic nervous system activates what is often termed the fight or flight response. This response is also known as sympathico-adrenal response of the body, as the pre-ganglionic sympathetic fibers that end in the adrenal medulla (but also all other sympathetic fibers) secrete acetylcholine, which activates the secretion of adrenaline (epinephrine) and to a lesser extent norepinephrine from it. Therefore, this response that acts primarily on the cardiovascular system is mediated directly via impulses transmitted through the sympathetic nervous system and indirectly via catecholamines secreted from the adrenal medulla.

Western science typically looks at the SNS as an automatic regulation system, that is, one that operates without the intervention of conscious thought. Some evolutionary theorists suggest that the sympathetic nervous system operated in early-man to maintain human survival (Origins of Consciousness, Robert Ornstein; et al.), as the sympathetic nervous system is responsible for priming the body for action.

Adapted from the Wikipedia article "Function", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki