Editing Peripheral nervous system (section)

==== 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" />