BioMedical Admissions Test (BMAT) 2026 – 400 Free Practice Questions to Pass the Exam

The hormone responsible for the fight or flight response is adrenaline, also known as epinephrine. This response is part of the body's acute stress reaction, which prepares an individual to either confront or flee from perceived threats. When faced with stress, the adrenal glands release adrenaline into the bloodstream, leading to a variety of physiological changes. These changes include increased heart rate, dilation of the airways to enhance oxygen intake, increased blood flow to muscles, and heightened alertness, all of which prepare the body to respond effectively to the situation.

In contrast, insulin and glucagon play crucial roles in regulating blood glucose levels but do not directly engage in the fight or flight response. Insulin lowers blood sugar levels by facilitating the uptake of glucose into cells, while glucagon increases blood sugar levels by promoting the release of glucose from the liver. Testosterone, though important for various bodily functions and development, is not involved in the acute stress response that adrenaline mediates. Therefore, adrenaline is specifically recognized as the hormone that triggers the fight or flight response, making it the correct answer.