Which of the following is a physiological response to acute stress?

• A. Decreased pupil size
• B. Dilated pupils
• C. Slowed breathing
• D. Decreased blood pressure

Answer: (B)

When acute stress hits, the body activates the sympathetic branch of the autonomic nervous system, triggering the fight-or-flight response. A key physiological change is pupil dilation, caused by sympathetic stimulation releasing norepinephrine that relaxes the iris dilator muscles. This widening lets in more light and sharpens vision, helping you respond quickly to a threat or challenge. The other options don’t fit this pattern: pupil size would not decrease under acute stress, breathing typically speeds up rather than slows, and blood pressure generally rises rather than falls. So pupil dilation is the hallmark physiological response in this scenario.