Which statement correctly describes the effects of the sympathetic and parasympathetic divisions on heart rate, digestion, and pupil size?

• A. Parasympathetic decreases heart rate, increases digestion, constricts pupils
• B. Sympathetic decreases heart rate, increases digestion, constricts pupils
• C. Parasympathetic increases heart rate, decreases digestion, dilates pupils
• D. Sympathetic increases heart rate, reduces digestion, dilates pupils

Answer: (D)

The question shows how the autonomic nervous system uses its two divisions to regulate organs during different states. In general, the sympathetic division gears the body up for action, while the parasympathetic division promotes rest and maintenance.

The correct statement reflects the fight-or-flight pattern: when sympathetic activation occurs, heart rate increases to boost blood flow, digestion activity is reduced as energy is diverted elsewhere, and the pupils dilate to allow more light and improve vision. This combination is characteristic of preparing the body to respond to a stimulus.

In calmer conditions, the parasympathetic division does the opposite: it slows the heart, promotes digestion, and constricts the pupils. The other options describe opposite effects that don’t align with the typical sympathetic response.