Editing Peripheral nervous system (section)

===Autonomic nervous system===
The [[autonomic nervous system]] (ANS) controls involuntary responses to regulate physiological functions.<ref name=":0">{{Cite journal|last=Laight|first=David|date=September 2013|title=Overview of peripheral nervous system pharmacology|journal=Nurse Prescribing|volume=11|issue=9|pages=448–454|doi=10.12968/npre.2013.11.9.448|issn=1479-9189}}{{Dead link|date=May 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The brain and spinal cord of the [[central nervous system]] are connected with organs that have smooth muscle or cardiac muscle, such as the heart, bladder, and other cardiac, exocrine, and endocrine related organs, by ganglionic neurons.<ref name=":0" /> The most notable physiological effects from autonomic activity are pupil constriction and dilation, and salivation of saliva.<ref name=":0" /> The autonomic nervous system is always activated, but is either in the sympathetic or parasympathetic state.<ref name=":0" /> Depending on the situation, one state can overshadow the other, resulting in a release of different kinds of [[neurotransmitters]].<ref name=":0" />

==== Sympathetic nervous system ====
The [[sympathetic system]] is activated during a "fight or flight" situation in which mental stress or physical danger is encountered.<ref name=":0" /> Neurotransmitters such as [[norepinephrine]], and [[epinephrine]] are released,<ref name=":0" /> which increases heart rate and blood flow in certain areas like muscle, while simultaneously decreasing activities of non-critical functions for survival, like digestion.<ref name=":1" /> The systems are independent to each other, which allows activation of certain parts of the body, while others remain rested.<ref name=":1" />

==== Parasympathetic nervous system ====
Primarily using the neurotransmitter [[acetylcholine]] (ACh) as a mediator, the [[parasympathetic system]] allows the body to function in a "rest and digest" state.<ref name=":1" /> Consequently, when the parasympathetic system dominates the body, there are increases in salivation and activities in digestion, while heart rate and other sympathetic response decrease.<ref name=":1" /> Unlike the sympathetic system, humans have some voluntary controls in the parasympathetic system. The most prominent examples of this control are urination and defecation.<ref name=":1" />

==== Enteric nervous system ====
There is a lesser known division of the autonomic nervous system known as the [[enteric nervous system]].<ref name=":1">{{Cite journal|last=Matic|first=Agnella Izzo|date=2014|title=Introduction to the Nervous System, Part 2: The Autonomic Nervous System and the Central Nervous System|url=http://eds.b.ebscohost.com/eds/pdfviewer/pdfviewer?sid=3ecac6d9-040d-48a2-87cb-cb214913ff07%40sessionmgr103&vid=&hid=114|journal=AMWA Journal: American Medical Writers Association Journal (AMWA J)|issn=1075-6361}}{{Dead link|date=May 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Located only around the digestive tract, this system allows for local control without input from the sympathetic or the parasympathetic branches, though it can still receive and respond to signals from the rest of the body.<ref name=":1" /> The enteric system is responsible for various functions related to gastrointestinal system.<ref name=":1" />