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Diagram of the stress response showing how the brain activates ACTH which causes cortisol and leads to physical reactions such as increased blood pressure and sweating
Stressis a biological and psychological response experienced upon encountering a threat that we feel we do not have the resources to deal with.
A stressor is a stimulus (or threat) that causes stress, e.g., an exam, divorce, the death of a loved one, moving house, or loss of job.
Sudden and severe stress generally produces:
Firstly, our body judges a situation and decides whether or not it is stressful. This decision is made based on sensory input and processing (i.e., the things we see and hear in the situation) and also on stored memories (i.e., what happened the last time we were in a similar situation).
If the situation is judged as being stressful, the hypothalamus (at the base of the brain) is activated.
The hypothalamus in the brain is in charge of the stress response. When a stress response is triggered, it sends signals to two other structures: thepituitary glandand theadrenal medulla.
The Hypothalamic-Pituitary-Adrenal (HPA) System
Chronic stress response: hypothalamic-pituitary-adrenal system (HPA) system.
Sympathomedullary Pathway (SAM)
The hypothalamus also activates the adrenal medulla. The adrenal medulla is part of theautonomic nervous system (ANS).
The ANS is the part of theperipheral nervous systemthat acts as a control system, maintaining homeostasis in the body. These activities are generally performed without conscious control.
The adrenal medulla secretes the hormone adrenaline. This hormone gets the body ready for a fight-or-flight response. The physiological reaction includes an increased heart rate.
Adrenaline leads to the arousal of thesympathetic nervous systemand reduced activity in the parasympathetic nervous system.
Adrenaline creates changes in the body, such as decreases (indigestion) and increased sweating, increased pulse, and blood pressure.
Once the ‘threat’ is over, theparasympathetic branchtakes control and brings the body back into a balanced state.
No ill effects are experienced from the short-term response to stress, and it further has survival value in an evolutionary context.
Evaluation
Strengths
Weakness
References
Currie, A. R., & Symington, T. (1955). The pathology of the pituitary and adrenal glands in systemic disease in man.Proceedings of the Royal Society of Medicine, 48(11), 908.
Olivia Guy-Evans, MSc
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
Saul McLeod, PhD
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
