Definition of "fight-or-flight" [fight-or-flight]

• All the coordinated physiological responses that the sympathetic nervous system initiates in response to stress or other emergency situations. (noun)

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• "First, there is an alarm stage, like what Cannon called the fight-or-flight syndrome."
• "Called the fight-or-flight response, it relies on a complex relay of chemicals in the body to mobilize key systems."
• "It accomplishes this through two mirror-image operating modes: sympathetic, also known as the fight-or-flight mechanism, which releases adrenaline to speed up metabolic processes in response to a perceived threat; and parasympathetic, which releases the neurotransmitter acetylcholine via the body’s longest and largest nerve, the vagus to slow down and reverse the frenetic activity caused by the sympathetic response."