Final answer:
Epinephrine and norepinephrine are hormones associated with the body's fight-or-flight response, causing effects such as blood vessel constriction and increased heart rate to support immediate survival functions.
Step-by-step explanation:
Epinephrine and norepinephrine are catecholamines that play a critical role in the body's fight-or-flight response to extreme stress. These hormones are secreted by the adrenal medulla and the nervous system, and they exert their effects by constraining blood vessels, specifically causing the constriction of afferent arterioles, which in turn stops the blood flow into the nephrons in the kidneys. This action is part of the body's adaptive processes to prioritize functions that are crucial for immediate survival, such as redirecting blood flow to muscles, increasing heart rate, and respiration. Additionally, these hormones can trigger the renin-angiotensin-aldosterone system to manage blood pressure and fluid balance in the body.