Final answer:
In organs with dual innervation, the sympathetic and parasympathetic divisions generally have opposite effects such as speeding up or slowing down heart rate, respectively. Drugs may activate both systems and cancel out effects, maintaining organ function as usual. Together, both divisions maintain body homeostasis.
Step-by-step explanation:
The effects of the sympathetic and parasympathetic divisions of the autonomic nervous system are often complementary and antagonistic, regulating various organs and bodily functions. The sympathetic division is responsible for the "fight-or-flight" response, increasing heart rate, dilating airways, and redistributing blood towards muscles during stress. Conversely, the parasympathetic division facilitates "rest and digest" activities, decreasing heart rate and stimulating digestion and waste elimination. In certain instances, such as the effects induced by certain drugs, the action of both divisions can cancel each other out, resulting in no net change in organ function. Typically though, they work in balance to maintain homeostasis in the body.
Examples of dual innervation include the heart, which is stimulated to beat faster by the sympathetic division and to slow down by the parasympathetic division; or the digestive system, where the sympathetic division causes sphincters to contract and the parasympathetic division promotes digestive movement. The intricate connections of each system, such as the wide-reaching projections of the sympathetic division or the more targeted effects of the parasympathetic division, allow for a detailed and cooperative control over various physiological processes.