Biological Systems MCAT Practice Exam

Which hormone is primarily involved in the stress response?

1. Insulin

2. Testosterone

3. Cortisol

4. Glucagon

The correct answer is: Cortisol

Cortisol is primarily involved in the stress response and plays a pivotal role in the body's reaction to stressors. It is a steroid hormone produced by the adrenal glands and is often referred to as the "stress hormone." When the body experiences stress—whether it be physical, emotional, or psychological—cortisol is released as part of the hypothalamic-pituitary-adrenal (HPA) axis response. Cortisol helps mobilize energy by increasing glucose availability, facilitating immediate reactions to stress through heightened alertness, and influencing various bodily functions to prepare for "fight or flight" situations. It also helps regulate metabolism, immune responses, and other critical processes that are vital during stressful conditions. While insulin, testosterone, and glucagon play important roles in the body's metabolism and reproductive functions, they do not primarily mediate the body's response to stress in the same direct and profound way that cortisol does. This delineation establishes cortisol's unique position in managing stress reactions within biological systems.