Question

a pedestrian narrowly avoids being hit by an oncoming car. he notices that it takes a little while for his heart rate and respiratory rate to return to normal. this is likely because
the splanchnic nerves have become activated.
somatic motor neurons have increased the heart and respiratory rate.
the corticospinal pathway has become activated.
the sympathetic division has stimulated the adrenal medullae.
the parasympathetic nervous system dominates.

Explanation:

When a person has a near - miss (like avoiding a car), the sympathetic nervous system is activated. The sympathetic division stimulates the adrenal medullae to release epinephrine and norepinephrine. These hormones have a relatively long - lasting effect. Even after the immediate threat (the car) is gone, the hormones remain in the bloodstream for a while, keeping the heart rate and respiratory rate elevated until they are metabolized.

• The splanchnic nerves are part of the sympathetic nervous system but the key here is the adrenal medullae stimulation.
• Somatic motor neurons control voluntary muscle movement, not heart and respiratory rate.
• The corticospinal pathway is involved in voluntary motor control (e.g., movement of limbs), not in regulating heart and respiratory rate.
• If the parasympathetic nervous system dominated, it would act to decrease heart and respiratory rate more quickly (it is the "rest - and - digest" system), but the delay is due to the lingering effects of sympathetic - induced adrenal medullae hormones.

Answer:

the sympathetic division has stimulated the adrenal medullae.