MCAT Biology Question 54: Answer and Explanation
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Question: 54
9. Which of the following is a function of the parasympathetic nervous system?
- A. Increasing blood sugar during periods of stress
- B. Dilating the pupils to enhance vision
- C. Increasing oxygen delivery to muscles
- D. Decreasing heart rate and blood pressure
Correct Answer: D
Explanation:
The parasympathetic nervous system governs the "rest-and-digest" response. The parasympathetic nervous system slows the heart rate, decreases blood pressure, promotes blood flow to the GI tract, and constricts the pupils, among other functions. The sympathetic nervous system governs the fight-or-flight response, including increased heart rate and blood pressure, decreased blood flow to the digestive tract, and increased blood flow the muscles. Choice (D) is the only answer choice that represents a function of the parasympathetic nervous system.