stress reaction

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1. forcibly exerted influence; pressure.
2. in dentistry, the pressure of the upper teeth against the lower.
3. a state of physiological or psychological strain caused by adverse stimuli, physical, mental, or emotional, internal or external, that tend to disturb the functioning of an organism and which the organism naturally desires to avoid. stress reactions are elicited but should these reactions be inappropriate or inadequate, they may lead to disease states. The term is also used to refer to the stimuli that elicit such a state or stress reactions. Just as a bridge is structurally capable of adjusting to certain physical stresses, the human body and mind are normally able to adapt to the stresses of new situations. However, this ability has definite limits beyond which continued stress may cause a breakdown, although this limit varies from person to person.

Physical Stress. There are many kinds of physical stress, but they can be divided into two principal types, to which the body reacts in different ways. There is emergency stress, a situation that poses an immediate threat, such as a near accident in an automobile, a wound, or an injury. There is also continuing stress, such as that caused by changes in the body during puberty, pregnancy, menopause, acute and chronic diseases, and continuing exposure to excessive noise, vibration, fumes, chemicals, or other agents.

The body's reaction to emergency stress is set off by the adrenal medulla. The medulla of each adrenal gland is directly connected to the nervous system. When an emergency arises, it pours the hormone epinephrine into the bloodstream. This has the effect of speeding up the heart and raising the blood pressure, emptying sugar supplies swiftly into the blood, and dilating the blood vessels in the muscles to give them immediate use of this energy. At the same time, the pupils of the eyes dilate. (See also alarm reaction.)

The reaction of the body to continuing stress is even more complex. Again the principal organs are the adrenal glands, but after the first phase of alarm, the glands continue to produce a steady supply of hormones that apparently increase the body's resistance. This is in addition to specific defenses such as the production of antibodies to fight infection. If the stress is overwhelming, as in the case of an extensive third-degree burn or an uncontrollable infectious disease, the third phase, exhaustion of the adrenal glands, sets in, sometimes with fatal results.
Psychologic Stress. The emergency response of the body comes into play when a person merely foresees or imagines danger, as well as in real emergency situations. The thought of danger, or the vicarious experience of it in a thrilling story, play, or film, may be enough to cause the muscles to tense and the heart to start pounding. Psychologic situations can have the same effect. One of the best-known examples of this is “stage fright,” often characterized by tensed muscles and an increased heart rate. At times the person may not even be aware of the unconscious thought that produces this dramatic reaction.
Stress and Disease. In recent decades, there have been numerous attempts to find a direct correlation between certain diseases and a stressful environment or a personality type that responds to the environment in a certain way. However, while inappropriate activity and a hectic lifestyle can cause illness in some persons, a busy and productive person can actually be subject to less stress than one who feels trapped in a limited position with no hope for release or a sense of accomplishment.

The diseases most often associated with a stressful environment are, according to some scientists, coronary artery disease and “heart attack,” high blood pressure, and cancer. Studies of laboratory animals have demonstrated a connection between isolated and specific stimuli such as electric shock and separation from mates and the development of heart disease in these animals. The stressful variables in the human environment are, however, much more complex, and a stressful environment can be related to heart disease only as a risk factor (see type a behavior).

The postulated relationship between stress and the development of a malignancy is based on the theory that destructive emotions affect and in some way weaken the body's surveillance system, causing its immune response to fail to recognize and destroy malignant cells.

Although relaxation techniques can reduce blood pressure in persons with mild hypertension, there is no evidence that tension and stress cause the blood pressure to rise and stay at levels above normal.

Other diseases considered by some researchers to be related to stress include asthma, allergies, colitis, migraine headaches, and peptic ulcers. Even though the relationship is not clear and there are currently no hard data to support this, most health care providers are convinced that stress contributes to the worsening of symptoms and influences the impact a disease will have on the lives of some patients while other patients adapt to stress and seem to have no long-term deleterious reaction to it.
Coping Mechanisms. Unhealthy ways to cope with psychologic stress include drug abuse and alcoholism, smoking, abusive and violent behavior, and working harder to accomplish unrealistic or poorly defined goals. In order to deal with stress in an effective and healthy way, one must first identify sources of stress, either within oneself or in one's environment.

Job stressors are frequently related to disorganization in the work place, poor time management, and unrealistic or uncommunicated expectations of the employer. Another source of stress for the working person may be the lack of time for family and recreation because of job demands. Once job stressors are identified, some options are to change the stressful situation, modify the way one responds to stressors, or seek another job that is less stressful. In some instances learning to be more assertive and better able to communicate with supervisors and coworkers can reduce job-related stress.

Stressors in the home environment include negative self-concept; inadequate physical, cognitive, or behavioral resources; poor problem-solving skills; marital discord; ineffective parenting or lack of parenting skills; and lack of family support. Effective coping may require strategies to improve self-concept and build self-esteem, develop problem-solving skills, learn effective parenting, and establish a network of people who can give support. Exercise, improving one's nutritional status, making time for recreational activities, and utilizing relaxation techniques to relieve tension can also be healthy ways to cope with stress.
oxidative stress any of various pathological changes seen in living organisms in response to excessive levels of cytotoxic oxidants and free radicals in the environment.
stress reaction any of the biological reactions to adverse stimuli, physical, mental, or emotional, internal or external, that tend to disturb the organism's equilibrium; should these compensating reactions, physiological or psychological, be inadequate or inappropriate, they may lead to disorders. See alarm reaction, acute stress reaction, general adaptation syndrome, acute stress disorder, adjustment disorder, and posttraumatic stress disorder.

stress re·ac·tion

an acute emotional reaction related to extreme environmental threat or challenge.

stress reaction

an acute maladaptive emotional response to an actual or perceived stressor.

stress re·ac·tion

(stres rē-ak'shŭn)
1. An acute emotional reaction related to extreme environmental stress.
Synonym(s): acute situational reaction.
2. Repetitive osseous overload that occurs during high-impact exercise, but without fracture.
See: stress fracture

stress reaction

tissue reaction to imposed stress, including initialization of inflammation and tissue repair; ongoing repetitive stress is characterized by prolongation of inflammation and delayed healing


1. opposite action or counteraction; the response of a part to stimulation.
2. the phenomena caused by the action of chemical agents; a chemical process in which one substance is transformed into another substance or substances.

chain reaction
one which is self-propagating; a chemical process in which each time a free radical is destroyed a new one is formed.
coupled reaction
one in which the free energy released by one chemical reaction drives the other reaction.
dark reaction
photosynthetic reaction which fixes CO2 into sugar and which occurs without exposure to light. Called also Calvin cycle.
reaction of degeneration
the reaction to electrical stimulation of muscles whose nerves have degenerated, consisting of loss of response to a faradic stimulation in a muscle, and to galvanic and faradic stimulation in the nerve.
delayed reaction
a reaction, such as an allergic reaction, occurring hours to days after exposure to an inducer.
false negative reaction
an erroneously negative reaction to a test.
false positive reaction
an erroneously positive reaction to a test.
first set reaction
immune reaction
1. immune response; see also immunity.
2. formation of a papule and areola without development of a vesicle following smallpox vaccination.
lengthening reaction
reflex elongation of extensor muscles that permits flexion of a limb.
leukemic reaction, leukemoid reaction
a peripheral blood picture resembling leukemia or indistinguishable from it on the basis of morphological appearance alone, characterized by immature leukocytes in the blood.
reaction pattern analysis
designed to replace archaic, non-specific descriptions of the reactions of the skin to noxious influences; recommended categories are (1) perivascular dermatitis, (2) interface dermatitis, (3) vasculitis, (4) nodular and diffuse dermatitis, (5) intradermal vesicular and pustular dermatitis, (6) subepidermal vesicular and pustular dermatitis, (7) perifolliculitis, folliculitis and furunculosis, (8) fibrosing dermatitis, (9) panniculitis, (10) atrophic dermatosis, (11) mixed reaction patterns.
second set reaction
reaction specificity
lack of production of by-products in enzymatic reactions with yields of products being nearly 100%.
Strauss reaction
development of suppurative peritonitis, localized to the scrotal sac, in the guinea pig after the intraperitoneal injection of material containing Burkholderia mallei.
stress reaction
1. alarm reaction.
2. gross stress reaction.
reaction time
the time elapsing between the application of a stimulus and the resulting reaction.
wheal-flare reaction
a cutaneous sensitivity rection to skin injury or administration of antigen, due to histamine production and marked by edematous elevation and erythematous flare.


1. forcibly exerted influence; pressure, e.g. compression, tension.
2. the sum of the biological reactions to any adverse stimulus, physical, mental, or emotional, internal or external, that tends to disturb the homeostasis of an organism. Should these reactions be inappropriate, they may lead to disease states. The term is also used to refer to the stimuli that elicit the reactions, e.g. heat, nutritional, lactational, confinement, transportation. See also psychosomatic disease.

stress induced diarrhea of the horse
see acute undifferentiated and chronic undifferentiated diarrhea of the horse.
porcine stress syndrome
see porcine stress syndrome.
stress reaction
stress-starvation syndrome
said of sheep. See pregnancy toxemia.
stress testing
a test for evaluating circulatory response to physical stress produced by exercise. See also exercise testing.
References in periodicals archive ?
Radiologically, femoral periosteal stress reaction is described as the presence of the dreaded black line which is a transverse black line traversing the cortex that can be complete or incomplete.
The social worker's stress reactions (the object of the first-level analysis) are apparent in the composition of the radio.
Finally, teach how to effectively manage and reduce the intensity of stress reactions by using immediate relaxation response methods.
The significance of stress reactions depends on how much they interfere with a child's regular routine of play, school, and self care activities.
Ten instruments were administered to determine psychosocial reactions and sources of stress: (1) stress events, (2) posttraumatic stress reactions in exile scale, (3) appraisal of the refugee situation scale, (4) depression scale (Zung, 1965), (5) expectations scale, (6) competence scale (Bezinovic, 1990), (7) external locus of control scale (Bezinovic, 1990), (8) psychosocial climate scale, (9) family relation scale, and (10) structured interview.
By and large, the group's direct exposure to the war trauma was sparse, which prevented long-term stress reaction.
A quick-reference format the interactive assignments are grouped by behavioral problems including combat and operational stress reactions, postdeployment reintegration, survivor's guilt, anxiety, parenting problems related to deployment, and posttraumatic stress disorder
Wives of men who were deployed showed rates of diagnosis that were 24% higher for depressive disorders, 21%-40% higher for sleep disorders, 25%-29% higher for anxiety disorders, and 23%-39% higher for acute stress reaction and adjustment disorders, compared with wives of nondeployed men.
The junior guard has missed all four of Oregon's regular-season games with a stress reaction and pain in her lower right leg.
A scan has revealed the talented Liverpool Harriers youngster, who was recently crowned the outstanding under-15 female athlete of the year by England Athletics, is suffering from a stress reaction above her right ankle.
Knight's minutes have increased, and he no longer is bothered by a stress reaction in his leg.
Three different specialists have advised Boro that Mido's stress reaction in the pubic bone is a difficult condition to treat and that the only way the player will recover is through rest and rehabilitation.