The Biology of Emotion and Stress Chapter 12 The Biology of Emotion and Stress

Stress Stressor - An event that either strains or overwhelms the ability of an organism to adjust to the environment.

Types of Stressors Physiological stressors include extreme cold or heat, the invasion of dangerous microorganisms, and physical injury. Psychological stressors include the death of a relative or friend, an upcoming exam, and being fired from a job. Ben Fogle 2012

Stress Pressure - An expectation to behave in a specific way within a particular time frame. Conflict - The inability to satisfy two or more incompatible motives. Frustration - The obstruction of achieving a goal. Stress response - The psychological and physiological changes that occur when we encounter a stressor; determines whether we are able to adapt to the stressful experience.

Biological Reactions to Stressors General Adaptation Syndrome (GAS) - A pattern of physiological responses to a physiological or psychological stressor; all stressors produce this response. The GAS has three stages: Alarm stage Resistance stage Exhaustion stage Han Selye

The Alarm Stage Characterized by intense sympathetic nervous system arousal; also called alarm reaction. Emergency reaction mobilizes our resources and prepares us for “fight or flight,” enabling us to cope behaviorally with stressful experiences. Alarm reaction lasts for a relatively short time. When the stressor ends, the parasympathetic nervous system takes over, restoring our physiological reserves to pre-stressor levels. If the stressor continues, however, we enter the second stage of the GAS.

The Resistance Stage Characterized by the mobilization of physiological resources to cope with a prolonged stressor. All physiological systems not directly involved in stress resistance are inhibited in this stage. A prolonged stressor continues the hypothalamic activation causing an increased release of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland.

The Resistance Stage ACTH released into the bloodstream continues to stimulate the manufacture and release of glucocorticoid hormones (which provides continued energy supply) from the adrenal cortex. This sequence of structures, the hypothalamus, pituitary gland, and adrenal cortex, is part of the stress axis.

The Exhaustion Stage If the stressor continues indefinitely, an animal eventually depletes its physiological resources, resulting in failure of the body’s defense systems and eventually death. Overtraining syndrome - disorder caused by excessive training by athletes; characterized by decreased performance, chronic fatigue, mood changes, and evidence of a compromised immune system.

The Three Stages of the General Adaptation Syndrome

Diseases of adaptation An illness caused by the efforts of the body to cope with stressors. Essential hypertension Gastric or peptic ulcers Colitis Stress reactions can both cause these illnesses and intensify their severity.

Stress and Neuroplasticity Chronic stress suppresses cellular proliferation and leads to a shortening and loss of dendrites in the hippocampus. By preventing the cellular changes that accompany learning and memory, stressors can have a profound effect on the ability to learn and remember. Not all stress has negative consequences: Acute stress enhances both the immune system and the memory of potentially threatening events.

Coping With Stressors beneficial effects Distress - Negative stress Eustress - Positive stress with beneficial effects Different people respond differently to the same stressor. Some people have an intense alarm reaction to a stressor that causes only a low or moderate reaction in other people. These responsivity differences influence disease development

Coping Behaviors: Type A, Type B Type A - A set of behaviors that includes an excessive competitive drive, an intense sense of time urgency, and high aggressiveness. Type B - A set of behaviors that are relatively relaxed, patient, and easy-going. Type A’s are twice as likely to have a heart attack as type Bs Type A is an independent risk factor for developing coronary heart disease.

Why Are Type A’s More at Risk for Coronary Disease? Significantly more reactive to stressors. Have greater norepinephrine release which can accelerate arterial damage, enhance blood clot formation, and produce cardiac arrhythmias. Smoke more, sleep less, drink more caffeine Show more hostility and are quick-tempered anger, which appear to be independent risk factors for coronary heart disease.

Hardiness Is the ability to cope effectively with stressors because of - a high level of commitment a perception that change is a challenge rather than a threat a sense of control over events. May explain why some individuals thrive despite being raised in extremely dysfunctional circumstances, while others fail in the most advantageous environments.

Hardiness Hardy people are less biologically responsive to stressors; cope better under stress Hardy people have a greater sense of purpose, a stronger commitment to self, an internal locus of control, and experience less emotional stress. Hardiness has been shown to be inversely related to depression and fatigue.