Which of the following is under the control of the parasympathetic nervous system?

• A. Pupil dilation
• B. Increased respiratory rate
• C. Decreased heart rate
• D. Increased blood pressure

Answer: (C)

Verified step by step guidance

1. Understand the role of the parasympathetic nervous system: It is part of the autonomic nervous system responsible for 'rest and digest' functions, which generally conserve energy and promote maintenance activities.
2. Identify the functions typically associated with the parasympathetic nervous system: These include slowing the heart rate, increasing intestinal and gland activity, and relaxing sphincter muscles in the gastrointestinal tract.
3. Analyze each option: Pupil dilation and increased respiratory rate are typically associated with the sympathetic nervous system, which prepares the body for 'fight or flight' responses.
4. Consider the option of decreased heart rate: This is a classic function of the parasympathetic nervous system, as it works to conserve energy by reducing the heart rate.
5. Evaluate the option of increased blood pressure: This is generally a function of the sympathetic nervous system, which increases blood pressure to prepare the body for action.