Final answer:
The sympathetic nervous system triggers the fight-or-flight response, preparing the body for action during stressful situations by increasing heart rate, raising blood pressure, and releasing adrenaline.
Step-by-step explanation:
The sympathetic nervous system is a component of the autonomic nervous system that primes the body for action during stressful or threatening situations, also known as the fight-or-flight response. When faced with an immediate threat, such as encountering a wild animal, this system triggers a cascade of physiological changes. These include an accelerated heart rate, elevated blood pressure, dilated pupils, and inhibited digestion. Blood glucose levels surge to fuel the muscles, sweat glands activate to cool the body, and adrenaline floods the system to increase alertness and muscle readiness.
The activation of the sympathetic nervous system has evolved as a survival mechanism, allowing animals, including humans, to respond to danger quickly by preparing to either confront the threat or escape from it. This response can be remembered by associating the surprise one feels when encountering a snake, linking the word 'snake' with the 'sympathetic' to recall its sudden, intense activation. The fight-or-flight response is not only crucial in life-threatening situations but also can be elicited in high-stress environments, such as during a significant presentation or an important competition.