Final answer:
The fight-or-flight response is a function of the autonomic nervous system, specifically its sympathetic division, which prompts several physiological changes to deal with perceived threats.
Step-by-step explanation:
The fight-or-flight response to an emergency situation is a specific function of the autonomic nervous system. This involuntary response prepares the body to either confront or run away from perceived threats. The sympathetic division of the autonomic nervous system is activated, resulting in several physiological changes such as an increase in heart rate, enhanced airflow to the lungs, dilation of pupils, and the redistribution of blood flow away from the digestive tract towards the muscles and brain.
While many organ systems are affected during the fight-or-flight response, such as the cardiovascular, respiratory, and digestive systems, the autonomic nervous system is the primary system responsible for initiating and controlling this reaction. It acts through the release of hormones like cortisol and adrenaline, which provide the body with a burst of energy and strength required to deal with the stressor effectively.