Which hormones activate the sympathetic nervous system?

The activation of the sympathetic nervous system is primarily driven by epinephrine and norepinephrine. These two hormones are produced by the adrenal glands, specifically in the adrenal medulla, as part of the body's fight-or-flight response. When faced with stress or danger, the sympathetic nervous system mobilizes energy and prepares the body for immediate action.

Epinephrine, also known as adrenaline, increases heart rate, dilates airways, and provides a rapid infusion of glucose to the blood for quick energy. Similarly, norepinephrine works to increase blood flow to muscles and elevate blood pressure by constricting blood vessels. Together, they play a crucial role in enhancing alertness and physical readiness.

In contrast, cortisol is a hormone involved in longer-term stress responses and metabolism, and while it does have a role in the body's response to stress, it doesn't directly activate the sympathetic nervous system in the way that epinephrine and norepinephrine do. Other options mentioned consist of hormones that are not directly linked to the initiation of the sympathetic response.