Physiological Responses to Stress - B1

Question 1

General Adaptation Syndrome (GAS)

Answer 1

• The body responds the same way to any stressor (Selye, 1936).
• It responds in the following way:
  1. Alarm – Identify a stressor & the hypothalamus in the brain releases adrenaline & noradrenaline.

2. Resistance – If threat continues, the body releases hormones and sugar to give the body the energy to deal with the stressor. If stressor is chronic then elevated hormone levels can damage the cardiovascular system
3. Exhaustion – As threat continues, the resources needed to resist the stressor are drained. We start to experience the initial symptoms again. This can damage glands & weaken the immune system & damage the Cardiovascular System.

However, this explanation is very simple and over the years has been adapted to give clearer explanations of what happens when we experience stress. these are the SAM system and HPA system.

Question 2

Role of Sympathomedullary system (SAM) in stress in acute stress

Answer 2

• SAM Deals with Acute Stress – short term stressor/threat requiring an immediate response
• Aim of the SAM system is to provide 02 and glucose to the skeletal muscles to enable us to fight or flight.

The SAM system responds to an acute stressor in the following way:

1. Stressor is identified & hypothalamus activates the sympathetic nervous system causing the adrenal medulla to release adrenaline & noradrenaline.
2. This is what causes the feeling of stress
3. Once the stressor stops, the nervous system and body returns to a relaxed state

Question 3

Role of Hypothalamic-pituatary-adrenal (HPA) System in chronic stress

Answer 3

• HPA deals with chronic stress – a long term stressor/threat that continues for weeks/months.
• Aim of the HPA system is to provide energy for a long period of time. This response starts at the same time as the SAM response.
• The HPA responds to chronic stress in the following ways:
  1. Once a threat is detected, a hormone called CRF released
  2. CRF is detected by the pituitary gland and ACTH into the blood.
  3. This causes the release cortisol.
  4. Cortisol affects and suppresses the immune system which can increase the risk of illness.
  5. Once the threat disappears, the whole HPA response stops.

Question 4

Role of adrenaline in the stress response

Answer 4

• Adrenaline gets the body ready for the fight or flight response
• It does this by stimulating the sympathetic nervous system which increases heart rate, respiration, dilation of blood vessels to the brain and skeletal muscles.
• This response increases blood flow and 02 to the working muscles & the brain so that the body is ready to respond to the threat.

Question 5

Limitations of Viewing Stress as Purely a Physiological Response

Answer 5

• The physiological approach is too simplistic because everyone responds to stress differently / doesn’t individual differences This suggests that there is a role for cognitions in the stress response and that the physiological response is not a complete explanation.

• A criticism of research is that it has mainly used male participants and where research has used females it has shown significant gender differences in coping with stress. This shows that the idea of a single physiological response is too simplistic.