Final answer:
The adrenal medulla secretes catecholamines, including epinephrine and norepinephrine, which are crucial for the body's immediate stress response, or 'fight-or-flight' reaction.
Step-by-step explanation:
The adrenal medulla secretes a class of hormones known as catecholamines, which includes both epinephrine (adrenaline) and norepinephrine (noradrenaline). These hormones are integral to the body's acute stress response often referred to as the 'fight-or-flight' response. In this role, catecholamines increase heart rate, breathing rate, cardiac muscle contractions, and blood-glucose levels. They also assist in redistributing blood to important areas like the muscles and away from the skin and viscera. Catecholamines are synthesized from the amino acid tyrosine and are released into the bloodstream during stressful situations such as fear, anger, or physical exertion.