Final answer:
The sympathetic nervous system's effects are opposite to those of the parasympathetic nervous system. While the sympathetic system prepares the body for fight-or-flight responses during stress, the parasympathetic system supports rest-and-digest functions during relaxation.
Step-by-step explanation:
The effects of the sympathetic nervous system are essentially opposite of the parasympathetic nervous system. The sympathetic division is activated during stressful or emergency situations, initiating the fight-or-flight response. It increases heart rate, dilates airways, inhibits digestion, and directs blood flow to muscles. On the other hand, the parasympathetic division dominates during relaxed states, promoting the rest-and-digest response, decreasing heart rate, constricting airways, and stimulating digestion. Together, these two divisions of the autonomic nervous system work to maintain homeostasis in the body.