USA Biology Olympiad (USABO) Practice Exam

Which subdivision of the autonomic nervous system is crucial for an animal fleeing from a predator?

1. The sympathetic nervous system

2. The parasympathetic nervous system

3. The enteric nervous system

4. The central nervous system

The correct answer is: The sympathetic nervous system

The sympathetic nervous system plays a vital role in the body's response to perceived threats, often described as the "fight or flight" response. When an animal is confronted by a predator, the sympathetic nervous system is activated, triggering a series of physiological changes that prepare the body for immediate action. This includes increased heart rate, dilated airways, and mobilized energy stores, all of which enhance physical performance and readiness to either confront the threat or flee from it. The activation of the sympathetic nervous system also results in the release of stress hormones, such as adrenaline, which further enhances these physiological processes. This rapid response is essential for survival in dangerous situations, as it helps the animal effectively and quickly escape from a predator. The other systems mentioned, like the parasympathetic nervous system, are associated with rest and digest functions and would not be involved in such an acute stress response. The enteric nervous system primarily manages functions related to the gastrointestinal system, while the central nervous system includes the brain and spinal cord but is not a subdivision of the autonomic nervous system itself. Thus, the sympathetic nervous system is the correct answer due to its direct involvement in preparing the body for fleeing from danger.