Final answer:
The hormones secreted by the adrenal medulla are epinephrine and norepinephrine, which are key players in the body's fight-or-flight response, increasing heart rate, blood pressure, and energy metabolism.
Step-by-step explanation:
Adrenal Medulla Hormones
The hormones that are secreted by the adrenal medulla are epinephrine (adrenaline) and norepinephrine (noradrenaline), which are both catecholamines. These hormones play crucial roles in the body's fight-or-flight response during stress. Epinephrine accounts for 75 to 80 percent of adrenal medullary secretions. Both hormones function to increase heart rate, breathing rate, blood pressure, and blood glucose levels, as well as accelerating the breakdown of glucose in skeletal muscles and fats in adipose tissue. They bind to receptors on target cells, activating an enzyme that controls a second messenger system.
During extreme stress, epinephrine and norepinephrine act directly on the smooth muscles of blood vessels to constrict them, affecting kidney function and triggering the renin-angiotensin-aldosterone system. Once released into the bloodstream, they circulate in plasma, either freely or loosely associated with albumin.