Which of the following is NOT a function of the parasympathetic nervous system?

• A. Promoting salivation
• B. Dilating the pupils
• C. Stimulating digestion
• D. Decreasing heart rate

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the parasympathetic nervous system, which is part of the autonomic nervous system responsible for 'rest and digest' activities. It generally promotes relaxation and conserves energy.
2. Step 2: Review the functions of the parasympathetic nervous system. Key functions include promoting salivation, stimulating digestion, and decreasing heart rate. These actions align with its role in maintaining homeostasis during restful states.
3. Step 3: Contrast the parasympathetic nervous system with the sympathetic nervous system, which is responsible for 'fight or flight' responses. The sympathetic system typically dilates the pupils to enhance vision during stressful situations.
4. Step 4: Analyze the options provided in the question. Identify which functions align with the parasympathetic nervous system and which do not. Promoting salivation, stimulating digestion, and decreasing heart rate are parasympathetic functions, while dilating the pupils is a sympathetic function.
5. Step 5: Conclude that the correct answer is the function that does not belong to the parasympathetic nervous system, which is 'Dilating the pupils.' This action is characteristic of the sympathetic nervous system.