STRESS & ADAPTATION

According to Selye (1956), it is the non-specific response of the body to any kind of demand upon it.

According to Schafer (2000):- It is the arousal of mind and body in response to a demand made upon them.

A stressor is any person or situation that produces anxiety responses. It is important for the nurse to seek information about the stress producer for that patient.

• Environment stressors:- Noise, pollution, traffic, crowding & weather

• Physiological stressors:- Illness, injuries, hormonal fluctuation, inadequate sleep & nutrition

• Social stressors:-Financial problem, work demands, social event, losing a loved one

• Thought:-Negative self-talk, perfectionism

Models of Stress:-  

It assists the nurse to identify the stressor in a particular situation to predict the individual’s response. A nurse can use the knowledge of these model to assist point in strengthening the healthy coping response. The main models of stress are:-

1. Stimulus-based model
2. Response based model
3. Transaction-based model

1.Stimulus-Based Model ( Holmes & Rahe – 1960 ):-

According to this model, stress is defined as a stimulus, a life event or a set of circumstances that arouses physiologic & psychological reactions that may increase the individual’s vulnerability to illness.

Holmen & Rahe developed to Social Readjustment Rating Scale (SRRS) consisting of 43 life events which are both +ve and –ve in nature and considered stressful. The more stressors a person experience in a short period (1-2 years) the more likely that physical illness, the mental disorder will follow.

This theory also explains that many people of a high score on SRRS do not subsequently experience a serious problem and low scores do not guarantee a life free of the danger of stress.

One reason is that how the individual perceives & cope with each stressor, play an important role in determining the impact of stressors on each individual.

2.Response-Based Model:–

Selye stress response is characterized by a chain or pattern of a physiologic event called general adaptation syndrome.

General Adaptation Syndrome ( Dr.Hans Selye)

• A homeostatic mechanism is aimed at counteracting the everyday stress of living. If they are successful, the internal environment maintains normal physiological limits of temperature, chemistry, and pressure.
• If stress is extreme or long lasting, the normal mechanism may not be sufficient. In this case, the stress triggers a wide-ranging set of bodily changes called the (GAS) General Adaptation Syndrome.
• The 1^st pathway is the stimulation of the sympathetic division of the autonomic nervous system and adrenal medulla. This produces an immediate set of responses called the alarm reaction.
• 2^nd pathway called the resistance reaction involves the anterior Pituitary gland & adrenal cortex, the resistance reaction is slower to start, but its effects last longer.

(A) Alarm Reaction or Fight or Flight Response :

It is the body’s initial reaction to a stressor. It is a set of the reaction include:-

    Stressor

                        ↓  ← stimulate

         Hypothalamus

                      ↓  ← stimulate

    SNS(sympathetic nervous system)

                        ↓  ← stimulate

        Adrenal medulla

                      ↓  ← Releases

    Catecholamine

(epinephrine norepinephrine produces)

↓

Alarm reaction

(Fight or flight response)

A stress response is characterized by alarm reaction include:-

• Heart rate, the strength of cardiac muscle contraction increases, this circulate blood quickly to area.
• Blood vessels that supply to the skin, viscera except heart and lung constrict at the same time, blood supplying to skeletal muscle & brain dilates, these responses provide more blood to organs active in stress response.
• Red blood cells (RBC) production is increased leading to an increase in the ability of the blood to clot. It helps to control bleeding.
• The liver converts glycogen to glucose & release into the bloodstream which provides energy to fight.
• The rate of breathing increases & respiration passage widens to accommodate more air which enables the body to acquire more oxygen.
• production of saliva & digestive enzymes decreases.

 (B) Resistance Reaction:-

It is the 2^nd stage in stress response.

Stressor

                   ↓  ← stimulate

Hypothalamus

                 ↓  ← Releases

CRH, GHRH, TRH

                 ↓  ← stimulate

Anterior Pituitary

              ↓  ← Releases

(Fight or flight response)

ACTH – Stimulate adrenal cortex- Releases adrenal hormone- Glucocorticoid &  Mineralocorticoids
HGH-Stimulate Liver- Supplies energy through glyconeogenesis- Increases break down of fat
TSH– Stimulate thyroid gland– Supplies energy through the breakdown of carbohydrates

• Exhaustion Stage:-

In this, the cell starts to die & the organ weakens. A long term resistance reaction put a heavy demand on the body.

3.Transaction-Based Model:–

Lazarus (1966), stress theory encompasses a set of a cognitive, effective & adaptive response that arises out of the person-environment transaction. The person and the environment are inseparable, each affects & is affected by the other.
He emphasizes that people or groups differ in their sensitivity & vulnerability of certain types of events, as well as in their interpretation & reaction. In terms of illness, one person may respond with denial another with anxiety & still another with depression.