AQA Biopsychology Practice Exam

During the fight or flight response, the brain releases a variety of neurotransmitters and hormones to prepare the body to react to perceived threats. Norepinephrine is one of the key substances released, particularly from the locus coeruleus in the brainstem, which plays a crucial role in increasing alertness and arousal. This release enhances the ability to respond quickly to danger, as it increases heart rate, blood pressure, and energy availability.

While adrenaline, also known as epinephrine, is released from the adrenal glands into the bloodstream as part of the body's overall stress response, it is norepinephrine that primarily acts as a neurotransmitter in the brain during the immediate fight or flight response. Cortisol, a hormone, is released later during prolonged stress, and serotonin is more commonly associated with mood regulation rather than immediate stress response.

Thus, norepinephrine’s specific role in the brain's immediate activation during stressful situations makes it particularly significant in the context of the fight or flight response.