Editing Fight-or-flight response (section)

===Autonomic nervous system===
{{See also|Autonomic nervous system}}
The autonomic nervous system is a control system that acts largely unconsciously and regulates [[heart rate]], [[digestion]], [[respiratory rate]], [[pupillary dilation|pupillary response]], [[Micturition|urination]], and [[sexual arousal]]. This system is the primary mechanism in control of the fight-or-flight response and its role is mediated by two different components: the sympathetic nervous system and the parasympathetic nervous system.<ref name="Human Physiology - Janig">{{cite book|editor-last=Janig|editor-first=W|title=Human Physiology|year=1989|publisher=Springer-Verlag|location=New York, NY|pages=333–370|author1=Schmidt, A |author2=Thews, G |edition=2|chapter=Autonomic Nervous System}}</ref>

[[File:The Autonomic Nervous System.jpg|thumb|455x455px|Comparison of Sympathetic and Parasympathetic nervous systems]]

====Sympathetic nervous system====
{{See also|Sympathetic nervous system}}
The sympathetic nervous system originates in the [[spinal cord]] and its main function is to activate the arousal responses that occur during the fight-or-flight response.<ref name=":2">{{Cite book |last1=Myers |first1=David G. |title=Psychology |last2=DeWall |first2=C. Nathan |publisher=MacMillan Publishing |year=2021 |edition=13 |pages=422}}</ref> The sympathetic nervous system transfers signals from the dorsal hypothalamus, which activates the heart, increases vascular resistance, and increases blood flow, especially to the muscle, heart, and brain tissues.<ref name=":02">{{Cite journal |last1=Kozlowska |first1=Kasia |last2=Walker |first2=Peter |last3=McLean |first3=Loyola |last4=Carrive |first4=Pascal |date=2015 |title=Fear and the Defense Cascade: Clinical Implications and Management |journal=[[Harvard Review of Psychiatry]] |volume=23 |issue=4 |pages=263–287 |doi=10.1097/HRP.0000000000000065 |issn=1067-3229 |pmc=4495877 |pmid=26062169}}</ref> It activates the adrenal medulla, releasing catecholamines that amplify the sympathetic response. Additionally, this component of the autonomic nervous system utilizes and activates the release of [[norepinephrine]] by the adrenal glands in the reaction.<ref name="Autonomic Nervous System - Chudler2">{{cite web |last=Chudler |first=Eric |title=Neuroscience For Kids |url=http://faculty.washington.edu/chudler/auto.html |access-date=19 April 2013 |publisher=University of Washington}}</ref>

====Parasympathetic nervous system====
{{See also|Parasympathetic nervous system}}
The parasympathetic nervous system originates in the sacral spinal cord and [[Medulla oblongata|medulla]], physically surrounding the sympathetic origin, and works in concert with the sympathetic nervous system. It is known as the calming portion of the autonomic nervous system.<ref name=":22">{{Cite book |last1=Myers |first1=David G. |title=Psychology |last2=DeWall |first2=C. Nathan |publisher=MacMillan Publishing |year=2021 |edition=13 |pages=422}}</ref> While the sympathetic nervous system is activated, the parasympathetic nervous system decreases its response. Efferent [[Vagus nerve|vagal fibers]] originating from the nucleus ambiguous fire in parallel to the respiratory system, decreasing the vagal cardiac parasympathetic tone.<ref name=":03">{{Cite journal |last1=Kozlowska |first1=Kasia |last2=Walker |first2=Peter |last3=McLean |first3=Loyola |last4=Carrive |first4=Pascal |date=2015 |title=Fear and the Defense Cascade: Clinical Implications and Management |journal=[[Harvard Review of Psychiatry]] |volume=23 |issue=4 |pages=263–287 |doi=10.1097/HRP.0000000000000065 |issn=1067-3229 |pmc=4495877 |pmid=26062169}}</ref> After the fight or flight response, the parasympathetic system's main function is to activate the "rest and digest" response and return the body to [[homeostasis]]. This system utilizes and activates the release of the neurotransmitter [[acetylcholine]].<ref name="Autonomic Nervous System - Chudler">{{cite web |last=Chudler |first=Eric |title=Neuroscience For Kids |url=http://faculty.washington.edu/chudler/auto.html |access-date=19 April 2013 |publisher=University of Washington}}</ref>