Stress - Physiology Of Stress

Question 1

What is stress?

Answer 1

State of physiological or psychological strain caused by a stressor, tends to disturb the functioning of the body
- Mismatch between demands made upon an individual + ability to meet these demands

Question 2

Sympathomedullary (SAM) pathway

Answer 2

• Typically deals with short term effects of stress
  1. Hypothalamus activates sympathetic branch of ANS, causes adrenal medulla to release adrenaline
  2. Gets the body ready for fight or flight, increasing arousal of sympathetic NS

Question 3

Hypothalamic-pituitary-adrenal (HPA) axis

Answer 3

1. Hypothalamus activates pituitary gland
2. Causes ACTH to be released which acts on the adrenal cortex
3. Corticosteroids such as cortisol are then released
   - Liver increases release of glucose (gluconeogenesis), supress immune system

Question 4

Role of cortisol

Answer 4

• Constricts blood vessels & increases BP to enhance delivery of oxygenated blood
• Regulates blood glucose
• Ideal short-term, over time can lead to vessel damage + plaque build up - cardiovascular disorders
• Regulates body’s stress response, maintain bp, immune function & slows body’s inflammatory process

Question 5

Newcomer et al

Answer 5

Ps given levels of cortisol as high as those experiencing major stress events had poorer recall of prose passages compared to those given a lower dosage
- High levels do impact cognitive functions

Question 6

Selye- rats research

Answer 6

• Predicted a non-specific physiological response to a stressor
• Rats became ill (develop stomach ulcers) even when given harmless injections
• Became ill for the stress of the injections & humans react the same

Question 7

GAS - Selye

Answer 7

Long-term response to a stressor

Question 8

GAS - Alarm reaction

Answer 8

1. (HPA) stressor triggers hypothalamus to release CRF, stimulates pituitary gland to release ACTH - adrenal cortex - corticosteroids (cortisol) & (SAM) sympathetic NS stimulates production of adrenaline + noradrenaline.
   Body is prepared for fight or flight

Question 9

GAS - Resistance

Answer 9

2. PAS tries to help body cope with stress. If stressful situation no longer present, bp, hr goes back to normal. If stressor still there, body continues to release stress hormones, resistance declines further

Question 10

GAS - Exhaustion

Answer 10

3. Stressor persists + can’t be overcome - leads to exhaustion
   Adrenal glands are depleted, PNS fails, vulnerable to stress-related illness

Question 11

Evaluation of Seyle GAS

Answer 11

Strengths:
Experimental, objective measure

Weakness:
Different stressors have different responses, different people react to the same stressor in different ways
Ignores individual differences in humans - gender, personality
Different interpretations to a stressor
Suggests a universal response to stress