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Apr 26, 2021 · Therefore, we suggest the framework of the stress system should comprise five basic elements: stressful stimulus, stressor, stress, stress response, and stress effect ( Figure 1A ). In this framework, the stressful stimulus is the starting point, the effect is the end point, and stressor, stress, and stress response are cascades. Figure 1.
- Figure 2
Stress is a central concept in biology and has now been...
- Introduction: The Science of Stress
Introduction: The Science of Stress. The term stress was...
- Figure 2
- Overview
- Types of stress and effects
- Treatment
stress, in psychology and biology, any environmental or physical pressure that elicits a response from an organism. In most cases, stress promotes survival because it forces organisms to adapt to rapidly changing environmental conditions. For example, in response to unusually hot or dry weather, plants prevent the loss of water by closing microscop...
Stress may be acute, chronic, or traumatic. In humans, acute stress is characterized by immediate danger that occurs within a short span of time and that activates the fight-or-flight response of the sympathetic nervous system; narrowly avoiding an automobile accident and being chased by a dog are examples of acute stress. Chronic stress is characterized by the persistent presence of sources of frustration or anxiety that a person encounters every day. An unpleasant job situation, chronic illness, and abuse incurred during childhood or adult life are examples of factors that can cause chronic stress. This type of stress involves long-term stimulation of the fight-or-flight response. Traumatic stress is characterized by the occurrence of a life-threatening event that evokes fear and helplessness. Tornadoes, fires, and wars are examples of events capable of causing traumatic stress; these events sometimes lead to the development of post-traumatic stress disorder.
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In the case of chronic stress, there is little doubt that an individual’s success or failure in controlling potentially stressful situations can have a profound effect on his or her ability to function. The ability to “cope” with stress has figured prominently in psychosomatic research. Researchers have reported a statistical link between coronary heart disease and individuals exhibiting stressful behavioral patterns designated “Type A.” These patterns are reflected in a style of life characterized by impatience and a sense of time urgency, hard-driving competitiveness, and preoccupation with vocational and related deadlines.
Biochemical changes play an important role in mediating physiological responses to stress; these chemical changes can result in psychological disturbances. Most chemical changes associated with stress are a result of stimulation of the sympathetic nervous system, specifically the fight-or-flight response. In acute stress, this response triggers the release of substances called catecholamines, which include epinephrine, norepinephrine, and cortisol, from the adrenal glands. These substances prepare the body to react to immediate danger by increasing heart rate, increasing oxygen delivery to the brain, dilating blood vessels in skeletal muscles, and increasing blood glucose levels.
In chronic stress, continuous stimulation of the fight-or-flight response leads to constant production and secretion of catecholamines. This has a variety of physiological consequences, including hyperglycemia (high blood glucose levels), which can lead to type II diabetes mellitus, and hypertension (high blood pressure), which can lead to cardiovascular disease. Because some catecholamines such as norepinephrine act as neurotransmitters in the brain, these substances can alter cognition and other mental processes, leading to poor concentration, mood swings, agitation, depression, and anxiety. In addition, long-term stress-induced cortisol secretion from the adrenal glands can depress immune function, leading to increased risk of illness. High levels of cortisol also are associated with weight gain, particularly with the accumulation of excess abdominal fat. Prolonged norepinephrine release directly by neurons of the sympathetic nervous system can lead to depletion of stem cell populations in hair follicles, resulting in premature graying of the hair.
Various strategies have been successful in treating stress. Moderate stress may be relieved by exercise, meditation (e.g., yoga), sufficient rest, and modification of diet, such as decreasing intake of alcohol and caffeine. Severe stress may require psychotherapy to uncover and work through the underlying causes. A form of behaviour therapy known a...
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Apr 3, 2024 · The stress response begins in the brain (see illustration). When someone confronts an oncoming car or other danger, the eyes or ears (or both) send the information to the amygdala, an area of the brain that contributes to emotional processing. The amygdala interprets the images and sounds. When it perceives danger, it instantly sends a distress ...
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Dec 22, 2020 · Stress is good for you: Stress motivates you and helps you stay alert and focused. Stress is the silent killer: Stress causes irritability, fatigue, sickness, and death. Which of the above is true ...
- Arash Emamzadeh
May 24, 2022 · From a scientific perspective, however, stress is a complicated thing. In general, scientists think of stress as your body’s response to being pushed out of balance. But what causes stress, how your body responds to stress, and the long-term impacts of stress all involve many factors: physiological, behavioral, emotional, and cognitive.
Stress is recognized as an important issue in basic and clinical neuroscience research, based upon the founding historical studies by Walter Canon and Hans Selye in the past century, when the concept of stress emerged in a biological and adaptive perspective. A lot of research after that period has expanded the knowledge in the stress field. Since then, it was discovered that the response to ...
