What is the functional role of the autonomic nervous system's sympathetic vs parasympathetic divisions?

• A. Sympathetic triggers 'fight or flight' and parasympathetic promotes 'rest and digest'.
• B. Sympathetic slows heart rate; parasympathetic speeds digestion.
• C. Both divisions slow heart rate.
• D. Parasympathetic promotes thirst.

Answer: (A)

The autonomic nervous system has two divisions that usually produce opposite effects on organs to prepare the body for action or relaxation. The sympathetic division drives fight-or-flight responses, activating systems that mobilize energy and readiness for danger. The parasympathetic division promotes rest-and-digest activities, conserving energy and supporting maintenance like digestion and tissue repair. This makes the correct description the one that states the sympathetic triggers fight-or-flight while the parasympathetic promotes rest and digestion. The other statements mix up these roles—sympathetic does not slow heart rate, both divisions do not slow heart rate, and thirst is not a primary function of the parasympathetic system.