Explain the role of adrenaline in the fight or flight response.

The fight or flight repsponse is part of the autonomic nervous system in which the body reacts to stressful environmental triggers. adrenaline is the prominent hormone in this response. Adrenaline activates the sympathetic nervous system which causes an increase in heart rate, triggers blood vessels to dialate, in order to redirect blood flow to major organs. This is done with the purpose that the body may need to face the threatening stimuli or run away from the danger. Without the input from adrenaline, these changes would not occur which, evolutionarily, may lead to severe consequences.