What is the primary hormone produced by the adrenal medulla?

The primary hormone produced by the adrenal medulla is epinephrine, also known as adrenaline. The adrenal medulla is the inner part of the adrenal glands, which are located on top of the kidneys. Its main function is to release hormones that are part of the body's fight-or-flight response, which helps prepare the body for a quick reaction to stress or danger.

Epinephrine plays a crucial role in increasing heart rate, enhancing blood flow to muscles, and elevating blood glucose levels by promoting the conversion of glycogen to glucose in the liver. This rapid mobilization of energy and increase in cardiovascular capacity allows the body to respond effectively in emergencies.

Thyroxine is a hormone produced by the thyroid gland, which regulates metabolism. Cortisol is a glucocorticoid hormone produced by the adrenal cortex and is involved in the regulation of metabolism and stress response, but it is not produced by the adrenal medulla. Insulin, on the other hand, is produced by the pancreas and is primarily responsible for regulating blood glucose levels. Therefore, epinephrine is the only hormone among the options that is specifically associated with the adrenal medulla.