STRESS & ADAPTATION

Stress

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 demand made upon them.

A stressor is any person or situation that produce anxiety responses. It is important for nurse to seek information about 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 assist nurse to identify the stressor in a particular situation to predict the individual’s response. Nurse can use the knowledge of these model to assist point in strengthening 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 reaction that may increases the individuals 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, mental disorder will follow.

This theory also explain that many people of high score on SRRS do not subsequently experience serious problem and low score do not guarantee a life free of 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 physiologic event called general adaptation syndrome.

General Adaptation Syndrome ( Hans Selye)

  • Homeostatic mechanism are aimed at counteracting the everyday stress of living. If they are successful, internal environment maintain 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 1st pathway is stimulation of the sympathetic division of autonomic nervous system and adrenal medulla. This produces an immediate set of response called the alarm reaction.
  • 2nd pathway called the resistance reaction involves the anterior Pituitary gland & adrenal cortex , the resistance reaction is slower to start, but it effects last longer.

(a) Alarm Reaction or Fight or Flight Response :

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

Stressor

↓  ← stimulate

Hypothalamus

↓  ← stimulate

SNS

↓  ← stimulate

Adrenal medulla

↓  ← Releases

Catecholamine

(epinephrine nor epinephrine produces)

Alarm reaction

(Fight or flight response)

Stress response is characterized by alarm reaction include :-

  • Heart rate, 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 same time blood supplying to skeletal muscle & brain dilate, these response provide more blood to organ active in stress response.
  • Red blood cells (RBC) production is increased leading to an increase in ability of the blood to clot. It helps to control bleeding.
  • Liver convert glycogen to glucose & release into blood stream which provide energy to fight.
  • The rate of breathing increases & respiration passage widen to accommodate more air which enable the body to acquire more oxygen.
  • production of saliva & digestive enzyme decreases.

(b) Resistance Reaction :-

It is the 2nd stage in stress response.

Stressor

↓  ← stimulate

Hypothalamus

↓  ← Releases

CRH, GHRH,TRH

↓  ← stimulate

Anterior Pituitary

↓  ← Releases

(Fight or flight response)

↓                                                   ↓                                                 ↓

ACTH                                       HGH                                           TSH

      ↓← stimulate                         ↓   ← stimulate                       ↓  ← stimulate

Adrenal cortex                          Liver                                       Thyroid gland

↓← release                             ↓                                                 ↓

Adrenal Hormone                  Supplies energy                         Supplies energy through breakdown

( Glucocorticoid &                  through glyconeogenesis           of carbonhydrates

Mineralocorticoids)                & increase break down of fat

  • Exhaustion Stage :-

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

3.Transaction-Based Model :-

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