Biology of health and illness factors

For example, an infection was considered to result only from the proliferation of bacteria, while other kinds of ill health might result from viruses, toxins, accidents, or flaws in a person's genetic makeup.

Biology of health and illness factors

Stress both causes and modulates a diversity of physiological effects that can enhance resistance to disease or cause damage and thereby promote disease.


For example, stress-related hormones, such as cortisol and epinephrine, have protective and adaptive functions as well as damaging effects. This idea, first introduced by Hans Selyeis reemerging in contemporary biobehavioral research McEwen, Individual Biology of health and illness factors is important because it increases or decreases the pathophysiological cost of stress through diet, exercise, and other activities.

The maintenance of constant and appropriate internal conditions and functioning in the face of changing environmental demands is called homeostasis, an idea first developed by Walter Cannon The stress response, however, primarily involves reaction in an emergency.

This function evolved over millions of years and is critical to the survival of most animals, including humans, when external threats and dangers, such as predation, are encountered. The stress response consists of many coadapted and simultaneous shifts in the physiological functioning of the cardiovascular, respiratory, muscular, metabolic, immune, and central nervous systems.

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Physiological changes can be accompanied by altered emotional responses, enhanced vigilance, heightened appraisal of risk, enhanced memory storage and retrieval, and changes in motivation. Many aspects of the stress response, however, are inappropriate or maladaptive in the context of modern postindustrial societies.

The threats posed here are different from those our evolutionary ancestors faced. The National Academies Press. Instead, contemporary humans face ill-defined, diffuse, often chronic threats that cannot be resolved by fight or flight. Nevertheless, the ancient physiologic stress response is triggered when one experiences, for example, a threat to social position, damage to important interpersonal relationships, loss of possessions, or barriers to the achievement of goals.

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Because many difficulties of contemporary life and their accompanying stress cannot be rapidly resolved—as could many physical stressors—the stress response persists, homeostasis is not restored, and the response becomes dysfunctional rather than adaptive.

An increasing body of evidence indicates that stress is a potent contributor to illness Cohen and Herbert, ; Cohen et al. The continued and unproductive activation of the stress response, including the failure to shut off this response when it is not needed, called allostatic load, is discussed below.

The stress response is one aspect of an array of biologic and behavioral processes that either protect or cause damage. But chronic increase in cortisol throughout the diurnal cycle is associated with negative consequences, such as accelerated bone mineral loss and hyperglycemia.

Because the subjective experience of stress does not always correlate with physiological response Kirschbaum et al. Allostasis and Allostatic Load An important new attempt to understand the relationships between environmental and behavioral challenges and stressors, the physiological responses to these events, and disease uses the terms allostasis and allostatic load.

Allostasis is the maintenance of overall stability homeostasis through the constant adjustment and balancing of various components in the process of adapting to challenge.

Sterling and Eyer first used the term to describe cardiovascular system adjustments in response to rest Page 42 Share Cite Suggested Citation: Later, the idea was generalized to other physiologic mediators, such as adrenal cortisol and the catecholamines.

Allostatic load is the wear and tear the body experiences as a result of repeated allostatic response McEwen, ; McEwen and Stellar, Allostasis and allostatic load operate in all systems of the body and focus attention on the protective, as well as the damaging, property of the primary mediators of the stress response: The major aspects are summarized in Figure First, the brain integrates and coordinates behavioral and physiologic responses hormonal and autonomic to challenge.

Some challenges can be perceived as stressful; others are related to circadian rhythms and to coordination of the functions of sleep and waking with the environment. Second, individual differences in the capacity to cope with challenges are based on multilevel relationships between genetic, developmental, and experiential influences.

Third, intrinsic to the autonomic, neuroendocrine, and behavioral responses to challenge is the capacity to adapt allostasis ; indeed, neuroendocrine responses, such as the release of cortisol, are by nature protective and acute. Problems arise only when they persist, so efficient initiation and cessation of these responses is vital.

Negative effects result when allostatic responses to challenge or stress occur inappropriately or are terminated inefficiently. Fourth, allostasis has a price that is related to the degree of inefficiency in the response and to the number of challenges and stressors a person experiences.

Allostatic load is more than chronic stress. And it also includes contributions of lifestyle factors, such as diet, alcohol and tobacco use, physical activity, and sleep, through their influences on the production of stress hormones.

Biology of health and illness factors

Protective and Damaging Effects of Stress Mediators A behavioral response to challenge or stress can be protective or damaging. The risk of harm or disease can be increased by such patterns of behavior as hostility or aggression, and it can be reduced by cooperation and conciliation.

Cigarette-smoking, excessive alcohol consumption, high fat consumption, and exposure to physical hazards increase the risk, as does insufficient physical activity. The link of allostasis and allostatic load can be applied to various behavioral responses: Such behaviors as smoking, high alcohol consumption, and consumption of high-fat foods all have Page 43 Share Cite Suggested Citation:All of the different causes of mental illness—biological and genetic causes and the wide variety of environmental causes—plus the very similar risk factors dance together in a complex motion to lead to the diagnosis of a specific mental illness.

The determinants of health Introduction. Many factors combine together to affect the health of individuals and communities. Whether people are healthy or not, is determined by their circumstances and environment. Social & Cultural Factors Related to Health Part A: Recognizing the Impact Alexis Armenakis, MSIV How Social & Cultural Factors Relate to Health & Illness • Social scientists designate a difference between disease social factors, and biology also influence the theories & methods of a health.

Call for Proposals for Twenty-Seventh Monograph of Sociology of Health & Illness Mildred Blaxter New Writer's Prize The Editorial Board will like to offer their congratulations to Kelley Sams who is the winner of the .

There are many aspects affecting health and how a person experiences health or illness. The Biopsychosocial modal of health care as developed by Engel (, ) takes into account the connections between the Biological, Psychological and Social factors.

Biology of health and illness factors

What Biological Factors Are Involved in Mental Illness? Some mental illnesses have been linked to abnormal functioning of nerve cell circuits or pathways that connect particular brain regions.

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