Which hormone is secreted by the adrenal medulla during stress?

The hormone secreted by the adrenal medulla during stress is adrenaline, also known as epinephrine. In stressful situations, the body activates the "fight or flight" response, which is a physiological reaction that prepares the individual to either confront or flee from a perceived threat. The adrenal medulla plays a crucial role in this response by releasing adrenaline into the bloodstream.

Adrenaline causes several effects: it increases heart rate, enhances the delivery of oxygen and glucose to the muscles, and boosts energy production. These changes prepare the body for immediate physical action. This release of adrenaline occurs rapidly in response to stress and is a key component of the body's acute stress response.

In contrast, cortisol, which is secreted by the adrenal cortex, is associated more with long-term stress response rather than immediate reactions. Insulin is a hormone that regulates blood sugar levels and is not directly involved in the stress response. Thyroxine, on the other hand, is produced by the thyroid gland and is primarily involved in regulating metabolism rather than directly responding to stress. Thus, adrenaline is the primary hormone associated with the acute stress response elicited by the adrenal medulla.