Which of the following is NOT a result of the activation of the sympathetic nervous system?

• A. Increased blood pressure
• B. Decreased heart rate
• C. Release of adrenaline from the adrenal medulla
• D. Dilated pupils

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the role of the sympathetic nervous system (SNS). The SNS is part of the autonomic nervous system responsible for the 'fight or flight' response, which prepares the body to respond to stress or danger.
2. Step 2: Identify typical physiological effects of SNS activation. These include increased heart rate, increased blood pressure, dilation of pupils, and release of adrenaline (epinephrine) from the adrenal medulla.
3. Step 3: Analyze each option in the problem: Increased blood pressure is a known SNS effect; release of adrenaline is also triggered by SNS activation; dilated pupils occur due to SNS stimulation.
4. Step 4: Consider the option 'Decreased heart rate.' Since SNS activation generally increases heart rate to prepare the body for action, a decrease in heart rate is not consistent with SNS activation.
5. Step 5: Conclude that the option 'Decreased heart rate' is NOT a result of sympathetic nervous system activation, as it contradicts the typical physiological response.