Editing Autonomic nervous system (section)

===Sympathetic nervous system===
{{Main|Sympathetic nervous system}}
Promotes a [[fight-or-flight response]], corresponds with arousal and energy generation, and inhibits digestion
* Diverts blood flow away from the [[gastro-intestinal]] (GI) tract and [[skin]] via [[vasoconstriction]]
* Blood flow to [[skeletal muscle]]s and the [[lung]]s is enhanced (by as much as 1200% in the case of skeletal muscles)
* Dilates [[bronchioles]] of the lung through circulating [[epinephrine]], which allows for greater [[Pulmonary alveolus|alveolar]] oxygen exchange
* Increases [[heart rate]] and the [[contractility]] of cardiac cells ([[myocytes]]), thereby providing a mechanism for enhanced blood flow to skeletal muscles
* Dilates [[pupils]] and relaxes the [[ciliary muscle]] to the lens, allowing more light to enter the eye and enhances far vision
* Provides [[vasodilation]] for the [[coronary vessels]] of the [[heart]]
* Constricts all the intestinal [[sphincters]] and the urinary sphincter
* Inhibits [[peristalsis]]
* Stimulates [[orgasm]]
The pattern of innervation of the [[sweat gland]]—namely, the postganglionic [[Sympathetic nervous system|sympathetic nerve]] fibers—allows clinicians and researchers to use [[sudomotor]] function testing to assess dysfunction of the autonomic nervous systems, through [[electrochemical skin conductance]].