Which of the following is a key role of epinephrine in the body?

Epinephrine, also known as adrenaline, plays a crucial role in the body's response to stress and is key in the "fight-or-flight" response. One of its primary functions is to increase blood glucose levels. It does this by promoting glycogenolysis, which is the breakdown of glycogen into glucose in the liver, and stimulating gluconeogenesis, the synthesis of glucose from non-carbohydrate sources. This increase in glucose availability provides the body with a quick source of energy necessary for rapid physical responses to stress.

The other options do not accurately reflect the direct role of epinephrine. While epinephrine does have effects on the immune system, it is not primarily responsible for regulating immune response. It also inhibits digestion, rather than stimulating it, as it redirects energy away from non-essential functions during a stress response. Regarding blood pressure, epinephrine typically causes an increase, not a decrease, as it constricts certain blood vessels and increases heart rate, which raises blood pressure to optimize blood flow to vital organs during stress. Thus, the elevation of blood glucose levels is a central and critical function of epinephrine in the body.