By Jonny Lupsha, News Writer

BBC News reported that a woman recently woke up alone on a parked airplane. The Air Canada flight had landed in Toronto but the crew failed to awaken the passenger, who had to call for help to be rescued from the plane. Her story illustrates how the brain handles stress.

Tiffani Adams woke up freezing cold and still buckled in her seat several hours after her flight from Quebec landed in Toronto, according to the BBC News article. She used her phone to call a friend for help and was eventually found by a luggage cart operator. Although Adams told the BBC she has had recurring night terrors since the event, her story has one silver lining: It evidences just how well the human brain can bear up and handle stressful situations, sometimes quite remarkably, when it must.

Biochemical Components of Stress Response

When our brains perceive a large enough threat or source of urgent stress, we go into “fight-or-flight mode,” in which our brains make a quick decision to escape a dangerous situation or confront it head-on. There is also a biochemical component to this particular phenomenon. “Not surprisingly, there are hormones and tissues involved in the fight-or-flight response,” said Dr. John Medina, Affiliate Professor of Bioengineering at the University of Washington School of Medicine. “The first biochemical is a classic: adrenaline. In the United States, we call adrenaline ‘epinephrine,’ but it’s the same stuff.”

Dr. Medina said that the second biochemical in the equation is cortisol, which is in a class of chemicals called glucocorticoids. “Cortisol is involved in many regulatory aspects of the stress response. It is also involved in fueling up the body to get ready either to kick butt or kick dust. The way it does this is to increase the amount of glucose in the blood which is then available for any tissue that needs the extra boost.”

The HPA Axis

Dr. Medina also said that cortisol is “the critical hormonal component of something we call the ‘HPA Axis.” HPA stands for Hypothalamus-Pituitary-Adrenal Glands. “The hypothalamus lies near the base of our brains and is involved in some of our most primal feelings, including reactions to threat,” Dr. Medina said. “The pituitary is a little pea-shaped structure dangling below the hypothalamus.” One of its many jobs is supervising how we get out of harm’s way. Finally, to paraphrase Dr. Medina, the adrenal glands are very neuro-reactive structures that lie on the top of the kidneys.

When you’re suddenly faced with imminent danger, these parts of your body are activated in that order. According to Dr. Medina, the hypothalamus is “responsible not only for starting up the initial responses but also helping to regulate them once they’ve gotten started.” One of the things it kicks up is the pituitary gland, which in turn releases hormones into the blood stream. “Their task is to find the adrenal glands and stimulate them into action,” Dr. Medina said. Finally, the adrenal glands release cortisol, which fuels the body with extra glucose, and other chemicals, including adrenaline/epinephrine.

Tiffani Adams must have had quite a shock when she woke up alone and cold on a dark, empty, parked airplane. In such a situation, it’s not uncommon for fight-or-flight mode to kick in and for the body to receive a jolt of energy needed to deal with such a dangerous situation. By triggering various organs and glands to deal with sudden danger, the brain sets off a chain reaction for survival.

Dr. John J. Medina contributed to this article. Dr. Medina is an Affiliate Professor of Bioengineering at the University of Washington School of Medicine. He holds a Ph.D. in Molecular Biology from Washington State University. In 2004, he was appointed to the rank of Affiliated Scholar at the National Academy of Engineering.