Final answer:
The stress response activates two key chemicals: hormones and neurotransmitters, which include adrenaline, cortisol, and others, with varying effects depending on the body's response pathway. The fight-or-flight response is initiated by the sympathetic nervous system and HPA axis under stress, affecting nearly all bodily functions.
Step-by-step explanation:
The stress response involves two kinds of chemicals: hormones and neurotransmitters. These can be hard to keep track of when following a sympathetic response because the same substance can have significantly different effects, and sometimes totally opposite effects, depending on where and how it's received in your body.
Fight-or-Flight Response Induced by Stress
Under stress, the sympathetic nervous system triggers the adrenal glands to release adrenaline, leading to the fight-or-flight response, including increased heart rate and energy availability. The hypothalamic-pituitary-adrenal (HPA) axis also becomes active, releasing hormones such as cortisol from the adrenal cortex that affect virtually every organ and prepare the body for urgent action.
Short-Term and Long-Term Stress Responses
The short-term stress response involves the immediate release of epinephrine and norepinephrine. In contrast, the long-term stress response involves the release of corticosteroids like cortisol, which affect glucose metabolism and have anti-inflammatory properties, but can weaken the immune system if levels remain elevated for too long.