What is the role of the adrenal medulla?

• A. To secrete thyroid hormones
• B. To secrete adrenaline and noradrenaline in response to stress
• C. To produce insulin
• D. To regulate metabolism

Answer: (B)

The adrenal medulla is an important part of the adrenal glands, which are located on top of the kidneys. Its primary role is to secrete adrenaline (also known as epinephrine) and noradrenaline (norepinephrine) in response to stress. This secretion is crucial during the body's "fight or flight" response, where these hormones prepare the body to react to perceived threats.

When released into the bloodstream, adrenaline and noradrenaline increase heart rate, elevate blood pressure, and boost energy supplies by breaking down glycogen into glucose. They also facilitate increased blood flow to muscles and decrease blood flow to non-essential systems, all of which are vital responses to acute stress or danger.

This function is distinct from that of other components in the endocrine system. For instance, the thyroid hormones are secreted by the thyroid gland, insulin is produced by the pancreas, and metabolic regulation involves a complex interplay of hormones from various glands, including insulin and thyroid hormones, but not directly from the adrenal medulla. Therefore, the role of the adrenal medulla in secreting adrenaline and noradrenaline is specific and essential for immediate stress response, distinguishing it from the functions attributed to the other choices.