““The sympathetic nervous system (SNS) mediates the body’s response to arousing circumstances, for example, producing the famed “fight or flight” stress response. To use the feeble joke told to first-year medical students, the SNS mediates the “four Fs—fear, fight, flight, and sex.” Particular midbrain/brain-stem nuclei send long SNS projections down the spine and on to outposts throughout the body, where the axon terminals release the neurotransmitter norepinephrine.””
![“It was at Harvard not quite forty years ago that I went into an anechoic [totally silent] chamber not expecting in that silent room to hear two sounds: one high, my nervous system in operation, one low, my blood in circulation. The reason I did not expect to hear those two sounds was that they…” quote by John Cage](https://sms4smile.com/quotes/img-quotes/153/john-cage-2094_blood_it-was-at-harvard-not-quite-forty-years_56114.jpg)
