Stress 16.02.23 Flashcards
How is stress as a response characterised (2)
- somatic (physical; body)
- psychological (mind)
These overlap and are both mediated via the brain
What is the definition of somatic (physical) stress?
Physical, emotional and subjective experiences associated with damage of body tissue and bodily threat (e.g. pain and inflammation)
What is the definition of psychological stress?
Emotional strain or tension resulting from adverse or demanding circumstances, often involving anticipation
What is Eustress?
- good stress
- positive stress which is beneficial and motivating; typically striving for a goal which is within reach
What is distress?
- negative stress
- this is damaging and harmful. Typically occurs when a challenge or threat is not resolved by coping or adaptation
What did Selye’s syndrome find?
That different insults could cause the same disease
1. Alarm - threat or stressor is identified and body goes into a state of fight or flight and alarm
2. Adaptation - body engages defensive countermeasures
3. Exhaustion - body runs out of defences and the resources are depleted
What is allostasis?
How complex systems adapt in changing environments, by changing set-points
What is an allostatic load?
Refers to cumulative exposure to stressors, which I’d unrelieved leads to systems ‘wearing out’ and this can have long-term effects
What are the 5 elements of the human stress response?
- Biochemical
- Physiological
- Behavioural
- Cognitive
- Emotional
Which nervous systems and processes mediate stress responses?
- autonomic nervous system
- sympathetic-adrenal-medullary (SAM)
- hypothalamo-pituitary axis (HPA)
- these responses lead to changes that influence future responses to stress, also reflecting brain plasticity
How does the sympathomedullary pathway create stress as a bodily response?
- Hypothalamus activates the adrenal medulla
- Adrenal medulla (controlled by the ANS) releases adrenaline and noradrenaline into the bloodstream
- Fight or flight responses. Hormones also increase heart rate and blood pressure etc…
- This produces energy
How does the pituitary-adrenal system activate stress as a bodily response?
- Higher brain centres activate hypothalamus
- Hypothalamus releases corticotrophin (CRF)
- Pituitary gland releases adrenocorticotrophic (ACTH)
- Adrenal cortex releases corticosteroids
- These causes changes e.g. liver releases energy and immune system is suppressed
What are 2 chemicals involved in the SNS fight or flight stress response?
- glucocorticoids (cortisol)
- catecholamines (adrenaline and noradrenaline)
How is the immune system affected by stress?
- inflammation and immune response are mediated and modified by adrenaline and cortisol
How does acute and chronic stress affect the immune response?
Acute: immune suppression
Chronic: partial immune suppression + low grade inflammatory response
